̽��ֱ�� of Cambridge - School of the Biological Sciences

Growing wildflowers on disused urban land can damage bee health

jg533 — Tue, 15 Apr 2025 23:01:26 +0000

̽��ֱ��metals have previously been shown to damage the health of pollinators, which ingest them in nectar as they feed, leading to reduced population sizes and death. Even low nectar metal levels can have long-term effects, by affecting bees’ learning and memory - which impacts their foraging ability.

Researchers have found that common plants including white clover and bindweed, which are vital forage for pollinators in cities, can accumulate arsenic, cadmium, chromium and lead from contaminated soils.

Metal contamination is an issue in the soils of cities worldwide, with the level of contamination usually increasing with the age of a city. ̽��ֱ��metals come from a huge range of sources including cement dust and mining.

̽��ֱ��researchers say soils in cities should be tested for metals before sowing wildflowers and if necessary, polluted areas should be cleaned up before new wildflower habitats are established.

̽��ֱ��study highlights the importance of growing the right species of wildflowers to suit the soil conditions.

Reducing the risk of metal exposure is critical for the success of urban pollinator conservation schemes. ̽��ֱ��researchers say it is important to manage wildflower species that self-seed on contaminated urban land, for example by frequent mowing to limit flowering - which reduces the transfer of metals from the soil to the bees.

̽��ֱ��results are published today in the journal Ecology and Evolution.

Dr Sarah Scott in the ̽��ֱ�� of Cambridge’s Department of Zoology and first author of the report, said: “It’s really important to have wildflowers as a food source for the bees, and our results should not discourage people from planting wildflowers in towns and cities.

“We hope this study will raise awareness that soil health is also important for bee health. Before planting wildflowers in urban areas to attract bees and other pollinators, it’s important to consider the history of the land and what might be in the soil – and if necessary find out whether there’s a local soil testing and cleanup service available first.”

̽��ֱ��study was carried out in the post-industrial US city of Cleveland, Ohio, which has over 33,700 vacant lots left as people have moved away from the area. In the past, iron and steel production, oil refining and car manufacturing went on there. But any land that was previously the site of human activity may be contaminated with traces of metals.

To get their results, the researchers extracted nectar from a range of self-seeded flowering plants that commonly attract pollinating insects, found growing on disused land across the city. They tested this for the presence of arsenic, cadmium, chromium and lead. Lead was consistently found at the highest concentrations, reflecting the state of the soils in the city.

̽��ֱ��researchers found that different species of plant accumulate different amounts, and types, of the metals. Overall, the bright blue-flowered chicory plant (Cichorium intybus) accumulated the largest total metal concentration, followed by white clover (Trifolium repens), wild carrot (Daucus carota) and bindweed (Convolvulus arvensis). These plants are all vital forage for pollinators in cities - including cities in the UK - providing a consistent supply of nectar across locations and seasons.

There is growing evidence that wild pollinator populations have dropped by over 50% in the last 50 years, caused primarily by changes in land use and management across the globe. Climate change and pesticide use also play a role; overall the primary cause of decline is the loss of flower-rich habitat.

Pollinators play a vital role in food production: many plants, including apple and tomato, require pollination in order to develop fruit. Natural ‘pollination services’ are estimated to add billions of dollars to global crop productivity.

Scott said: “Climate change feels so overwhelming, but simply planting flowers in certain areas can help towards conserving pollinators, which is a realistic way for people to make a positive impact on the environment.”

̽��ֱ��research was funded primarily by the USDA National Institute of Food and Agriculture.

Reference
Scott, SB and Gardiner, MM: ‘Trace metals in nectar of important urban pollinator forage plants: A direct exposure risk to pollinators and nectar-feeding animals in cities.’ Ecology and Evolution, April 2025. DOI: 10.1002/ece3.71238

Wildflowers growing on land previously used for buildings and factories can accumulate lead, arsenic and other metal contaminants from the soil, which are consumed by pollinators as they feed, a new study has found.

Our results should not discourage people from planting wildflowers in towns and cities. But.. it’s important to consider the history of the land and what might be in the soil."

Sarah Scott

Chicory growing in a vacant lot

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Licence type:

Attribution-Noncommerical

Cambridge researchers named 2025 Schmidt Science Fellows

Anonymous — Mon, 07 Apr 2025 11:55:17 +0000

Now in its eighth year, the Fellowship provides financial support for a postdoctoral placement of one to two years at a world-class research institution.

̽��ֱ��funding equips scientists to apply their knowledge to a new field of study with the goal of accelerating discoveries, and to develop their leadership potential.

Dr Poppy Oldroyd, a 2025 Schmidt Science Fellow from the Department of Engineering, plans to pioneer a new frontier in understanding brain communication through optical measurements, ultimately advancing treatments for memory-related diseases.

̽��ֱ��human brain communicates through intricate networks of neurons, crucial for learning and memory. However, how these neural conversations translate into memory formation remains a mystery in neuroscience. Oldroyd’s research aims to use light-based tools, like advanced optogenetics, to explore these pathways in detail. By uncovering how specific brain circuits contribute to learning and memory, this research could revolutionise our understanding of these essential brain functions.

Ultimately, this knowledge may enhance our comprehension of memory-related disorders like Alzheimer’s disease and epilepsy.

Dr Matthew McLouglin, a 2025 Schmidt Science Fellow from the Cambridge Stem Cell Institute, plans to develop tools to study how our cells age in real time. This will help us understand why we age and how we might promote healthy aging to improve quality of life in the elderly.

Our DNA is organised into structures called chromosomes. Each chromosome has a protective cap, the ‘telomere’, which is partially lost with each cell division. In old age, cells cannot function properly due to the loss of telomeres, increasing the risk of age-related diseases such as cancer and dementia. McLoughlin will use cutting-edge imaging technology to track the loss of telomeres over time, understanding how telomeres are lost and why this stops cells from functioning.

Oldroyd and McLoughlin join a community of 209 Schmidt Science Fellows from nearly 40 countries who are leaders in interdisciplinary science.

“Philanthropic funding of scientific research, and especially support of early-career researchers, has never been more important,” said Wendy Schmidt, who co-founded Schmidt Science Fellows with her husband, Eric.

“By providing Schmidt Science Fellows with support, community, and freedom to work across disciplines and gain new insights, we hope they’ll tackle some of the world’s most vexing challenges, achieve breakthroughs and help create a healthier, more resilient world for all.”

Established in 2017, Schmidt Science Fellows is a programme of Schmidt Sciences delivered in partnership with the Rhodes Trust.

̽��ֱ��2025 Fellows represent 15 nationalities, including researchers from Jordan and the United Arab Emirates for the first time in the programme’s history.

This year’s cohort will work on a range of problems from cancer treatment to quantum technologies to sustainability.

Alongside their research Placement, Fellows participate in a 12-month interdisciplinary Science Leadership Programme.

Each year, Schmidt Science Fellows works in partnership with more than 100 universities to identify candidates for the Fellowship.

Nominees are selected via an application process that includes an academic review with panels of experts in their original disciplines and final interviews with a multidisciplinary panel of scientists and private sector leaders.

“ ̽��ֱ��Schmidt Science Fellows Program is cultivating a dynamic global community of remarkable scientists and champions of interdisciplinary research,” said Stu Feldman, Chief Scientist at Schmidt Sciences.

“Their work exemplifies Schmidt Sciences’ commitment to support pioneering approaches that will drive the next era of discovery and innovation.”

̽��ֱ��2025 Schmidt Science Fellows represent 27 nominating universities, including, for the first time, McGill ̽��ֱ�� in Canada, RWTH Aachen ̽��ֱ�� in Germany, Tecnológico de Monterrey in Mexico, ̽��ֱ�� of California, Los Angeles in the US, and ̽��ֱ�� of Groningen in the Netherlands.

Two ̽��ֱ�� of Cambridge researchers are among the thirty-two early career researchers, tackling issues from improving food security to developing better medical implants, who have been announced as the 2025 Schmidt Science Fellows.

Schmidt Science Fellows

Poppy Oldroyd (left) and Matthew McLoughlin (right)

Yes

AI can be good for our health and wellbeing

cjb250 — Mon, 07 Apr 2025 08:00:08 +0000

Cambridge researchers are looking at ways that AI can transform everything from drug discovery to Alzheimer's diagnoses to GP consultations.

Students from across the country get a taste of studying at Cambridge at the Cambridge Festival

zs332 — Thu, 27 Mar 2025 10:17:46 +0000

We were delighted to welcome pupils from Warrington’s Lymm High School, Ipswich High School, ̽��ֱ��Charter School in North Dulwich, Rickmansworth School, Sutton Valance School in Maidstone as well as schools closer to home such as St Peter’s Huntingdon, Fenstanton Primary School, Barton Primary School, Impington Village College and St Andrews School in Soham.

Running over two days (25/26 March 2025) and held in the Cambridge Sports Centre, students went on a great alien hunt with Dr Matt Bothwell from the Institute of Astronomy, stepped back in time to explore Must Farm with Department of Archaeology and the Cambridge Archaeological Unit as well as learning to disagree well with Dr Elizabeth Phillips from ̽��ֱ��Woolf Institute.

Schools had a choice of workshops from a range of departments including, how to think like an engineer and making sustainable food with biotechnology with researchers from the Department of Chemical Engineering and Biotechnology, as well as the chance to get hands-on experience in the world of materials science and explore how properties of materials can be influenced by temperature at the Department of Materials Science and Metallurgy.

̽��ֱ��Department of Veterinary Medicine offered students the opportunity to find out what a career in veterinary medicine may look like with workshops on animal x-rays, how different professionals work together to treat animals in a veterinary hospital as well as meeting the departments horses and cows and learn how veterinarians diagnose and treat these large animals.

Students also had the opportunity to learn about antibodies and our immune system with the MRC Toxicology Unit. ̽��ֱ��students learnt about the incredible job antibodies do defending our bodies against harmful invaders like bacteria and viruses.

Alongside this, a maths trail, developed by Cambridgeshire County Council, guided students around the West Cambridge site whilst testing their maths skills with a number of problems to solve.

Now in their third year, the Cambridge Festival schools days are offering students the opportunity to experience studying at Cambridge with a series of curriculum linked talks and hands on workshops.

̽��ֱ��Cambridge Festival runs from 19 March – 4 April and is a mixture of online, on-demand and in-person events covering all aspects of the world-leading research happening at Cambridge. ̽��ֱ��public have the chance to meet some of the researchers and thought-leaders working in some of the pioneering fields that will impact us all.

Over 500 KS2 and KS3 students from as far away as Warrington got the chance to experience studying at the ̽��ֱ�� of Cambridge with a selection of lectures and workshops held as part of the Cambridge Festival.

Students make antibody keychains during a workshop with the MRC Toxicology Unit

Yes

Conservation efforts are bringing species back from the brink

sc604 — Tue, 18 Mar 2025 18:30:46 +0000

A major review of over 67,000 animal species has found that while the natural world continues to face a biodiversity crisis, targeted conservation efforts are helping bring many species back from the brink of extinction.

Genetic study reveals hidden chapter in human evolution

sc604 — Tue, 18 Mar 2025 10:00:00 +0000

Using advanced analysis based on full genome sequences, researchers from the ̽��ֱ�� of Cambridge have found evidence that modern humans are the result of a genetic mixing event between two ancient populations that diverged around 1.5 million years ago. About 300,000 years ago, these groups came back together, with one group contributing 80% of the genetic makeup of modern humans and the other contributing 20%.

For the last two decades, the prevailing view in human evolutionary genetics has been that Homo sapiens first appeared in Africa around 200,000 to 300,000 years ago, and descended from a single lineage. However, these latest results, reported in the journal Nature Genetics, suggest a more complex story.

“ ̽��ֱ��question of where we come from is one that has fascinated humans for centuries,” said first author Dr Trevor Cousins from Cambridge’s Department of Genetics. “For a long time, it’s been assumed that we evolved from a single continuous ancestral lineage, but the exact details of our origins are uncertain.”

“Our research shows clear signs that our evolutionary origins are more complex, involving different groups that developed separately for more than a million years, then came back to form the modern human species,” said co-author Professor Richard Durbin, also from the Department of Genetics.

While earlier research has already shown that Neanderthals and Denisovans – two now-extinct human relatives – interbred with Homo sapiens around 50,000 years ago, this new research suggests that long before those interactions – around 300,000 years ago – a much more substantial genetic mixing took place. Unlike Neanderthal DNA, which makes up roughly 2% of the genome of non-African modern humans, this ancient mixing event contributed as much as 10 times that amount and is found in all modern humans.

̽��ֱ��team’s method relied on analysing modern human DNA, rather than extracting genetic material from ancient bones, and enabled them to infer the presence of ancestral populations that may have otherwise left no physical trace. ̽��ֱ��data used in the study is from the 1000 Genomes Project, a global initiative that sequenced DNA from populations across Africa, Asia, Europe, and the Americas.

̽��ֱ��team developed a computational algorithm called cobraa that models how ancient human populations split apart and later merged back together. They tested the algorithm using simulated data and applied it to real human genetic data from the 1000 Genomes Project.

While the researchers were able to identify these two ancestral populations, they also identified some striking changes that happened after the two populations initially broke apart.

“Immediately after the two ancestral populations split, we see a severe bottleneck in one of them—suggesting it shrank to a very small size before slowly growing over a period of one million years,” said co-author Professor Aylwyn Scally, also from the Department of Genetics. “This population would later contribute about 80% of the genetic material of modern humans, and also seems to have been the ancestral population from which Neanderthals and Denisovans diverged.”

̽��ֱ��study also found that genes inherited from the second population were often located away from regions of the genome linked to gene functions, suggesting that they may have been less compatible with the majority genetic background. This hints at a process known as purifying selection, where natural selection removes harmful mutations over time.

“However, some of the genes from the population which contributed a minority of our genetic material, particularly those related to brain function and neural processing, may have played a crucial role in human evolution,” said Cousins.

Beyond human ancestry, the researchers say their method could help to transform how scientists study the evolution of other species. In addition to their analysis of human evolutionary history, they applied the cobraa model to genetic data from bats, dolphins, chimpanzees, and gorillas, finding evidence of ancestral population structure in some but not all of these.

“What’s becoming clear is that the idea of species evolving in clean, distinct lineages is too simplistic,” said Cousins. “Interbreeding and genetic exchange have likely played a major role in the emergence of new species repeatedly across the animal kingdom.”

So who were our mysterious human ancestors? Fossil evidence suggests that species such as Homo erectus and Homo heidelbergensis lived both in Africa and other regions during this period, making them potential candidates for these ancestral populations, although more research (and perhaps more evidence) will be needed to identify which genetic ancestors corresponded to which fossil group.

Looking ahead, the team hopes to refine their model to account for more gradual genetic exchanges between populations, rather than sharp splits and reunions. They also plan to explore how their findings relate to other discoveries in anthropology, such as fossil evidence from Africa that suggests early humans may have been far more diverse than previously thought.

“ ̽��ֱ��fact that we can reconstruct events from hundreds of thousands or millions of years ago just by looking at DNA today is astonishing,” said Scally. “And it tells us that our history is far richer and more complex than we imagined.”

̽��ֱ��research was supported by Wellcome. Aylwyn Scally is a Fellow of Darwin College, Cambridge. Trevor Cousins is a member of Darwin College, Cambridge.

Reference:
Trevor Cousins, Aylwyn Scally & Richard Durbin. ‘A structured coalescent model reveals deep ancestral structure shared by all modern humans.’ Nature Genetics (2025). DOI: 10.1038/s41588-025-02117-1

Modern humans descended from not one, but at least 2 ancestral populations that drifted apart and later reconnected, long before modern humans spread across the globe.

Our history is far richer and more complex than we imagined

Aylwyn Scally

Jose A Bernat Bacete via Getty Images

Plaster reconstructions of the skulls of human ancestors

Yes

Scientists identify genes that make humans and Labradors more likely to become obese

jg533 — Thu, 06 Mar 2025 19:03:04 +0000

Researchers studying British Labrador retrievers have identified multiple genes associated with canine obesity and shown that these genes are also associated with obesity in humans.

̽��ֱ��dog gene found to be most strongly associated with obesity in Labradors is called DENND1B. Humans also carry the DENND1B gene, and the researchers found that this gene is also linked with obesity in people.

DENND1B was found to directly affect a brain pathway responsible for regulating the energy balance in the body, called the leptin melanocortin pathway.

An additional four genes associated with canine obesity, but which exert a smaller effect than DENND1B, were also mapped directly onto human genes.

“These genes are not immediately obvious targets for weight-loss drugs, because they control other key biological processes in the body that should not be interfered with.

But the results emphasise the importance of fundamental brain pathways in controlling appetite and body weight,” said Alyce McClellan in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience, and joint first author of the report.

“We found that dogs at high genetic risk of obesity were more interested in food,” said Natalie Wallis in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience, and joint first author of the report.

She added: “We measured how much dogs pestered their owners for food and whether they were fussy eaters. Dogs at high genetic risk of obesity showed signs of having higher appetite, as has also been shown for people at high genetic risk of obesity.”

̽��ֱ��study found that owners who strictly controlled their dogs’ diet and exercise managed to prevent even those with high genetic risk from becoming obese - but much more attention and effort was required.

Similarly, people at high genetic risk of developing obesity will not necessarily become obese, if they follow a strict diet and exercise regime - but they are more prone to weight gain.

As with human obesity, no single gene determined whether the dogs were prone to obesity; the net effect of multiple genetic variants determined whether dogs were at high or low risk.

̽��ֱ��results were published on 6 March in the journal 'Science'.

“Studying the dogs showed us something really powerful: owners of slim dogs are not morally superior. ̽��ֱ��same is true of slim people. If you have a high genetic risk of obesity, then when there’s lots of food available you’re prone to overeating and gaining weight unless you put a huge effort into not doing so,” said Dr Eleanor Raffan, a researcher in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience who led the study.

She added: “By studying dogs we could measure their desire for food separately to the control owners exerted over their dog’s diet and exercise. In human studies, it’s harder to study how genetically driven appetite requires greater willpower to remain slim, as both are affecting the one person.”

̽��ֱ��current human obesity epidemic is mirrored by an obesity epidemic in dogs. About 40-60% of pet dogs are overweight or obese, which can lead to a range of health problems.

Dogs are a good model for studying human obesity: they develop obesity through similar environmental influences as humans, and because dogs within any given breed have a high degree of genetic similarity, their genes can be more easily linked to disease.

To get their results, the researchers recruited owners with pet dogs in which they measured body fat, scored ‘greediness’, and took a saliva sample for DNA. Then they analysed the genetics of each dog. By comparing the obesity status of the dog to its DNA, they could identify the genes linked to canine obesity.
Dogs carrying the genetic variant most associated with obesity, DENND1B, had around 8% more body fat than those without it.

̽��ֱ��researchers then examined whether the genes they identified were relevant to human obesity. They looked at both large population-based studies, and at cohorts of patients with severe, early onset obesity where single genetic changes are suspected to cause the weight gain.

̽��ֱ��researchers say owners can keep their dogs distracted from constant hunger by spreading out each daily food ration, for example by using puzzle feeders or scattering the food around the garden so it takes longer to eat, or by choosing a more satisfying nutrient composition for their pets.

Raffan said: “This work shows how similar dogs are to humans genetically. Studying the dogs meant we had reason to focus on this particular gene, which has led to a big advance in understanding how our own brain controls our eating behaviour and energy use.”

̽��ֱ��research was funded by Wellcome, the BBSRC, Dogs Trust, Morris Animal Foundation, MRC, France Genomique consortium, European Genomic Institute for Diabetes, French National Center for Precision Diabetic Medicine, Royal Society, NIHR, Botnar Foundation, Bernard Wolfe Health Neuroscience Endowment, Leducq Fondation, Kennel Club Charitable Trust.

Reference
Wallis, N J et al: ‘Canine genome-wide association study identifies DENND1B as an obesity gene in dogs and humans.’ Science, March 2025. DOI: 10.1126/science.ads2145

Researchers at the ̽��ֱ�� of Cambridge have discovered genes linked to obesity in both Labradors and humans. They say the effects can be over-ridden with a strict diet and exercise regime.

Dogs at high genetic risk of obesity showed signs of having higher appetite, as has also been shown for people at high genetic risk of obesity.

Natalie Wallis

James Barker on Unsplash

Labrador licking nose

Yes

Licence type:

Attribution-Noncommerical

Pledge to phase out toxic lead ammunition in UK hunting by 2025 has failed

jg533 — Thu, 06 Mar 2025 09:14:35 +0000

̽��ֱ��pledge, made in February 2020 by the UK’s nine leading game shooting and rural organisations, aimed to benefit wildlife and the environment and ensure a market for the healthiest game meat food products.

But a Cambridge team, working with the ̽��ֱ�� of the Highlands and Islands, has consistently shown that lead shot was not being phased out quickly enough to achieve a complete voluntary transition to non-toxic ammunition by 2025. In a final study, published on 6 March in the journal Conservation Evidence, the team concludes that the intended transition has failed.

̽��ֱ��team has closely monitored the impact of the pledge every year since its introduction, recruiting expert volunteers to buy whole pheasants from butchers, game dealers and supermarkets across Britain and recover embedded shotgun pellets for analysis.

In 2025, the study - called SHOT-SWITCH - found that of 171 pheasants found to contain shot, 99% had been killed with lead ammunition.

This year, for the first time, the team also analysed shotgun pellets found in red grouse carcasses shot in the 2024/25 shooting season and on sale through butchers’ shops and online retailers. In all 78 grouse carcasses from which any shot was recovered, the shot was lead.

“Many members of the shooting community had hoped that the voluntary pledge away from lead ammunition would avert the need for regulation. But the voluntary route has now been tested - with efforts made by many people - and it has not been successful,” said Professor Rhys Green in the ̽��ֱ�� of Cambridge’s Department of Zoology and lead author of the report.

Eating game meat killed using lead shot will expose people unnecessarily to additional dietary lead. Lead is toxic to humans even in very small concentrations; the development of the nervous system in young and unborn children is especially sensitive to its effects. As a result, many food safety agencies now advise that young children and pregnant women should avoid, or minimise, eating game meat from animals killed using lead ammunition.

Discarded shot from hunting also poisons and kills many tens of thousands of the UK’s wild birds each year.

Despite proposing the voluntary change, many shooting organisations and some individual shooters do not support proposed regulatory restrictions on lead ammunition.

Green said: “Private individuals pay a lot of money to shoot pheasants on some private estates - and people don’t like to change their habits. It’s a bit like wearing car seatbelts, or not smoking in pubs. Despite the good reasons for doing these things, some people were strongly against using regulation to achieve those changes, which are now widely accepted as beneficial. ̽��ֱ��parallel with shooting game with lead shotgun ammunition is striking.”

Danish shooters now say that the legal ban on lead introduced in Denmark around 30 years ago was justified. They say it has not reduced the practicality or popularity of their sport, and has increased its acceptability to wider society.

“Although a few large UK estates have managed to enforce non-lead ammunition on pheasant shoots, some have had to be quite draconian in order to do it, with the estate gamekeepers insisting on loading the guns for the shooters,” added Green.

In the 2020/21 and 2021/22 shooting seasons, over 99% of the pheasants studied were shot using lead ammunition. This figure dropped slightly to 94% in 2022/23 and 93% in 2023/24, with the remaining pheasants killed by ammunition made of steel or a metal called bismuth, before rising to 99% again in 2024/25.

Retail pressure

̽��ֱ��researchers also checked up on a pledge made by Waitrose in 2019 to stop selling game killed with lead ammunition.

They found that the retailer had been largely let down by suppliers, and that some of their shooters continued to shoot using lead despite making assurances to the contrary. As a result, Waitrose did not sell oven-ready pheasants at all between 2021 and 2023. It sold pheasants again in January 2024 and the 2024/25 season, but the researchers showed that the majority had been killed using lead shot.

In 2022 the National Game Dealers Association (NGDA), which buys game and sells it to the public and food retailers, also announced it would no longer sell game of any kind that had been shot using lead ammunition. But this pledge has since been withdrawn. ̽��ֱ��researchers bought 2024/25 season pheasants from three NGDA member businesses and found that all had been shot with lead ammunition.

Inside influence

̽��ֱ��researchers also analysed all articles relating to the voluntary transition published in the magazine of the UK’s largest shooting organisation, the British Association for Shooting and Conservation. They found that articles near the beginning of the five-year pledge communicated clear, frequent and positive messages about the effectiveness and practicality of non-lead shotgun ammunition.

But by 2023, mentions of the transition and encouragement to follow it had dropped dramatically.

̽��ֱ��upshot

At the request of the Defra Secretary of State, the UK Health & Safety Executive (HSE) has assessed the risks to the environment and human health posed by lead in shot and bullets. Its report, published in December 2024, proposes that the UK Government bans the use of lead shot and large calibre bullets for game shooting because of the risks they pose to the environment and health. This recommendation is currently under review by Defra ministers, with a response due in March 2025.

Steel shotgun pellets are a practical alternative to lead and can be used in the vast majority of shotguns, as can other safe lead-free alternatives. But the results of this study indicate UK hunters remain unwilling to make the switch voluntarily.

Since 2010, UK governments have preferred voluntary controls over regulation in many areas of environment and food policy and have suggested that regulation be used only as a last resort.

“Shooting organisations did a lot of questionnaire surveys when the pledge was introduced in 2020, and the results suggested many shooters thought the time had come to switch away from lead ammunition. Those responses stand in contrast to what we’ve actually measured for both pheasant and grouse,” said study co-author Dr Mark Taggart at the ̽��ֱ�� of the Highlands and Islands.

Toxic lead

A previous study led by Green and colleagues found that pheasants killed by lead shot contained many fragments of lead too small to detect by eye or touch, and too distant from the shot to be removed without throwing away a large proportion of otherwise useable meat. This means that eating pheasant killed using lead shot is likely to expose consumers to raised levels of lead in their diet, even if the meat is carefully prepared to remove whole shotgun pellets and the most damaged tissue.

Lead has been banned from use in paint and petrol for decades. It is toxic to humans when absorbed by the body and there is no known safe level of exposure. Lead accumulates in the body over time and can cause long-term harm, including increased risk of cardiovascular disease and kidney disease in adults. Lead is known to lower IQ in young children and affect the neurological development of unborn babies.

̽��ֱ��studies were part-funded by the RSPB, Waitrose & Partners, and an anonymous donor. They were supported by a group of unpaid volunteers, who are co-authors of the reports.

References

Green, R E et al: ‘ ̽��ֱ��proportion of common pheasants shot using lead shotgun ammunition in Britain has barely changed despite five years of voluntary efforts to switch from lead to non-lead ammunition.’ March 2025, Conservation Evidence. DOI: 10.52201/CEJ22/EXYS6184

Green, R E et al.: ‘Sampling of red grouse carcasses in Britain indicates no progress during an intended five-year voluntary transition from lead to non-lead shotgun ammunition.’ February 2025, Conservation Evidence. DOI: 10.52201/CEJ22/YYWM1722

A voluntary pledge made by UK shooting organisations in 2020 to replace lead shot with non-toxic alternatives by 2025 has failed, analysis by Cambridge researchers finds.

̽��ֱ��voluntary route has now been tested - with efforts made by many people - and it has not been successful.

Rhys Green

Andy Hay, RSPB

Adult pheasant

Yes

Licence type:

Attribution-Noncommerical