Downward mobility from top backgrounds even rarer than previously thought

Only a tiny fraction of children from the most privileged backgrounds will end up in working class jobs, suggesting that social mobility in the UK may be even more limited than previously thought.

Peer-Reviewed Publication

University of Kent

New research from the University of Kent, funded by the Leverhulme Trust, reveals that by age 30, only 10% of men and women from top backgrounds – such as the children of doctors, lawyers, and executives – are in working class occupations, while nearly seven in 10 hold highly paid or prestigious positions. Even when advantaged backgrounds are defined more broadly, downward mobility into working class roles remains limited to just 15%.

The study, conducted by Dr Robert de Vries and published in Social Science Research, suggests that previous research has overestimated rates of downward mobility by focusing exclusively on technical measures of occupational class, while ignoring the prestige attached to certain positions. This leads to people from elite backgrounds in highly sought after, prestigious roles – for example in the creative industries – being classified as downwardly mobile.

The research accounted for this by examining parental origins and destination occupations in terms of both prestige and class. As well as revealing substantially lower rates of downward mobility from the most privileged backgrounds, this also revealed pronounced gender differences. Men from advantaged backgrounds were more likely to enter highly paid roles in, for example, business or finance, whereas women from similar backgrounds were much more likely to pursue careers in teaching or creative professions. As a result, women from elite backgrounds frequently inherited their parents’ social status, but not their financial advantage, whereas men tend to inherit both.

Dr de Vries’ findings are based on an analysis of data from more than 94,000 respondents to the UK Labour Force Survey – the UK’s largest representative household survey.

Dr de Vries, Senior Lecturer in Quantitative Sociology at the University’s School of Social Policy, Sociology and Social Research, said: ‘This research shows that the UK’s ‘glass floor’ is even sturdier than we realised. The children of the most advantaged families face almost no risk of significant downward mobility – with the most likely outcome being a smooth path into a highly prestigious or highly paid job (or both). The study also reveals substantial gender inequality even among the children of privilege, with women from top backgrounds often ending up in roles that are prestigious but less financially rewarding than those of their male peers.

‘Falling sideways? Social status and the true nature of elite downward mobility’ (Robert de Vries) is published in Social Science Research, Vol 124.

Only a tiny fraction of children from the most privileged backgrounds will end up in working class jobs, suggesting that social mobility in the UK may be even more limited than previously thought.

New research from the University of Kent, funded by the Leverhulme Trust, reveals that by age 30, only 10% of men and women from top backgrounds – such as the children of doctors, lawyers, and executives – are in working class occupations, while nearly seven in 10 hold highly paid or prestigious positions. Even when advantaged backgrounds are defined more broadly, downward mobility into working class roles remains limited to just 15%.

The study, conducted by Dr Robert de Vries and published in Social Science Research, suggests that previous research has overestimated rates of downward mobility by focusing exclusively on technical measures of occupational class, while ignoring the prestige attached to certain positions. This leads to people from elite backgrounds in highly sought after, prestigious roles – for example in the creative industries – being classified as downwardly mobile.

The research accounted for this by examining parental origins and destination occupations in terms of both prestige and class. As well as revealing substantially lower rates of downward mobility from the most privileged backgrounds, this also revealed pronounced gender differences. Men from advantaged backgrounds were more likely to enter highly paid roles in, for example, business or finance, whereas women from similar backgrounds were much more likely to pursue careers in teaching or creative professions. As a result, women from elite backgrounds frequently inherited their parents’ social status, but not their financial advantage, whereas men tend to inherit both.

Dr de Vries’ findings are based on an analysis of data from more than 94,000 respondents to the UK Labour Force Survey – the UK’s largest representative household survey.

Dr de Vries, Senior Lecturer in Quantitative Sociology at the University’s School of Social Policy, Sociology and Social Research, said: ‘This research shows that the UK’s ‘glass floor’ is even sturdier than we realised. The children of the most advantaged families face almost no risk of significant downward mobility – with the most likely outcome being a smooth path into a highly prestigious or highly paid job (or both). The study also reveals substantial gender inequality even among the children of privilege, with women from top backgrounds often ending up in roles that are prestigious but less financially rewarding than those of their male peers.

‘Falling sideways? Social status and the true nature of elite downward mobility’ (Robert de Vries) is published in Social Science Research, Vol 124.

---

Journal

Social Science Research

DOI

10.1016/j.ssresearch.2024.103089 

Method of Research

Survey

Subject of Research

People

Article Title

Falling sideways? Social status and the true nature of elite downward mobility

 

The Arctic is the only ocean that has not seen a drop in legacy persistent organic pollutants decades after global regulations, says new Concordia study

Despite a 2001 ban worldwide, these harmful chemicals are still being carried north and damaging the polar ecosystems

Concordia University

 

image: 

Xianming Zhang: “Persistent organic pollutants are very stable, bioaccumulative and toxic, meaning they do not break down easily and can move through the global environment and accumulate up through the food chain."

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Credit: Concordia University

The presence of persistent organic pollutants (POPs) in all the world’s oceans but one has been in steady decline since 2001, when 152 countries agreed on a comprehensive global ban. The exception has been the Arctic Ocean, which has seen a sharp rise in POPs in its frigid waters over the past several decades.

In a paper published in the journal Science Advances, Concordia assistant professor Xianming Zhang reported a study with an international team of researchers on the effectiveness of global regulatory efforts and legislative measures on persistent organic pollutants (POPs) in the planetary marine environments. This study highlighted the success of source control measures demonstrated by a general decreasing trend in POP concentrations across various maritime regions. However, the Arctic Ocean and its marginal seas have experienced a rise in POP levels. Their presence poses potential dangers to animals and people as they enter the fragile ecosystem’s food web.

“Persistent organic pollutants are very stable, bioaccumulative and toxic, meaning they do not break down easily and can move through the global environment and accumulate up through the food chain, causing both environmental and health impacts” says Zhang, an assistant professor in the Department of Chemistry and Biochemistry and the co-director of Centre for Research in Molecular/Multiscale Modeling.

“Over the period when POPs were produced and reaching the environment, long-range atmospheric transport had been the main pathway through which POPs reached the Arctic. When source regulations are in place, ocean circulation plays a more important role in delivering historically emitted POPs to the Arctic. This is the rationale of this study,” Zhang explains.

The region’s cold waters extend the chemicals’ already long half-lives by decades in some cases, and its ocean current patterns and natural restrictions like ice cover make them more likely to stay there – a process known as “cold trapping.”

“Along with the health concerns they pose by entering the food web through animals like whales, seals and polar bears, POPs in the Arctic are also ethical issues as many of the chemicals are not produced or used in the Arctic but the Arctic population and ecosystems are exposed to higher levels of chemicals that are emitted from other parts of the world,” Zhang says.

Long-lasting lessons

The researchers carried out in-depth analyses of over 10,000 measurements of POPs in the global oceans over the past five decades. They found that not only are the chemicals being driven northwards by sea currents, but also some coastal areas are seeing a rise in POPs as chemicals embedded in river sediments slowly make their way to the oceans.

“Oceans have become the sinks for these chemicals, and ocean circulation is contributing more to their global transport to the Arctic now that the sources for atmospheric circulation have been restricted by the Stockholm Convention of 2001,” he explains.

He notes that the oceans are now both sinks and sources of POP contaminants as they move the chemicals northwards. Compared to the world’s other oceans, the Arctic counts the highest concentration of HCH, DDT and OCP pesticides in its waters.

These legacy POPs will take decades to degrade but they do offer some lessons for the present, Zhang says.

“We now have a clearer understanding of the processes these legacy POPs experience in the global environment, so we can largely reduce environmental and health impacts by considering the properties and processes that make chemicals into POPs even before a new chemical is produced or used in large quantities. Global partnership with different stakeholders is essential to achieve the goal” he says.

Different from POPs covered in this study, PFAS, so-called “forever chemicals,” are more concerning in term of their environmental and health impact disclosed by relatively recent studies including those by the Zhang group. Zhang says their research aims to understand sources, processes and impact of legacy and new POPs can help shape policy and legislative guidelines around them to minimize the hazards they pose to the environment.

“We need to point out that even though the Arctic is not seeing reduced concentrations of these POPs two decades after global source regulations, it does not mean that global chemical regulations are not working,” says Zhang. “Without those regulations, the situation would have been much worse.”

Read the cited paper: “Exploring global oceanic persistence and ecological effects of legacy persistent organic pollutants across five decades”

---

Journal

Science Advances

DOI

10.1126/sciadv.ado5534 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Exploring global oceanic persistence and ecological effects of legacy persistent organic pollutants across five decades

Major discovery on origin of writing in birthplace of civilization

Julia Musto
Tue 5 November 2024 
THE INDEPENDENT


Researchers have made another major stride in understanding humanity’s origins of writing.

In Mesopotamia, the birthplace of civilization, the earliest known writing system started around 3,000 BCE.

Developed by the Sumerians and written on clay tablets, the first cuneiform is largely sourced back to the urban city of Uruk, or modern day Iraq. Thousands of tablets have since been unearthed, as well as small stone cylinder seals that were often used as signatures.


Now, academics at Italy’s University of Bologna have identified links between the designs engraved on these 6,000-year-old cylinders and pictographs in proto-cuneiform script – which came before cuneiform – that emerged in Uruk.

“We wanted to see whether the traditional explanation of how writing was born in Mesopotamia in Uruk in the fourth millennium is really valid,” Professor Silvia Ferrara, the lead researcher, told The Independent on Monday.

The work was published Tuesday in the journal Antiquity.

Ferrara said that the findings add to previous research, which found that tokens were the devices that led to the possibility of writing.

The clay tokens came in multiple sizes, and are believed to have been shaped like the commodities of daily life.

A cylinder seal, left, and its design is imprinted on clay. Cylinder seals were made out of stone and are another piece of the puzzle in understanding the origins of writing in Mesopotamia (Franck Raux © 2001 GrandPalaisRmn (Musée du Louvre))

Ferrara said they are geometric and don’t have iconic imagery like these seals whereas the signs of the proto-cuneiform writing system start off as being being very iconographic: “They resemble things.”

“We realized that a number of images on the cylinder seals actually do resemble signs of the proto-cuneiform writing system that were used a couple of centuries later,” she said.

“Cylinder seals that are part of a network of exchanges between Uruk and other cities in its precinct ... were a responsible mechanism for the creation of writing.”

These findings mark the first time there’s been a link between the cylinder seal system and the invention of writing. The seals were also used as an accounting system, tracking various agricultural and textile goods.

Co-authors and research fellows Kathryn Kelley and Mattia Cartolano worked alongside Ferrara. Kelley explained that they wanted to understand what encouraged people to leap into a writing system.

“We wanted to try to establish the other kind of relationship from seals, originally prehistoric sealing technology, into writing,” she said. “And, that’s the link. The crucial link that we’re presenting in the paper is a first concrete set of a few signs where we can explicitly say: these are there before writing and they’re used in similar ways and they have some sort of semantic association that is carried over into the invention of writing.”


A proto-cuneiform tablet is seen in this image. Proto-cuneiform was an ancient Mesopotamia writing system that came at the end of the fourth millennium BC (Courtesy of CDLI - Cuneiform Digital Library Initiative)

Ferrara said that the researchers are not saying that the seals are the only source for writing. The findings give nuance to human understanding of the practice’s origins.

“But, we are showing some very concrete evidence that pre-literate image traditions, and in this case seals, are part of the stimulus for moving the information technology in a different direction,” she said.

The four original inventions of writing are in Mesopotamia, Egypt, China, and the South American Mayan culture. There may, however, be another source. There are cases in modern India and Pakistan and Easter Island. Both systems remain undeciphered.

“And, for instance, with the case of Easter Island, we actually have more than indirect evidence right now that leads us to think that this is in fact the fifth invention of writing in the world,” Ferrara said.

The origin of writing in Mesopotamia is tied to designs engraved on ancient cylinder seals

Università di Bologna

 

image: 

Example of a cylinder seal (left) and its design imprinted onto clay (right)

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Credit: Franck Raux © 2001 GrandPalaisRmn (Musée du Louvre)

The origins of writing in Mesopotamia lie in the images imprinted by ancient cylinder seals on clay tablets and other artifacts. A research group from the University of Bologna has identified a series of correlations between the designs engraved on these cylinders, dating back around six thousand years, and some of the signs in the proto-cuneiform script that emerged in the city of Uruk, located in what is now southern Iraq, around 3000 BCE.

The study—published in Antiquity—opens new perspectives on understanding the birth of writing and may help researchers not only to gain new insights into the meanings of the designs on cylinder seals but also to decipher many still-unknown signs in proto-cuneiform.

" The conceptual leap from pre-writing symbolism to writing is a significant development in human cognitive technologies," explains Silvia Ferrara, professor in the Department of Classical Philology and Italian Studies at the University of Bologna and lead researcher. "The invention of writing marks the transition between prehistory and history, and the findings of this study bridge this divide by illustrating how some late prehistoric images were incorporated into one of the earliest invented writing systems."

Among the first cities to emerge in Mesopotamia, Uruk was an immensely important centre throughout the fourth millennium BCE, exerting influence over a large region extending from southwestern Iran to southeastern Turkey.

In this region, cylinder seals were created. Typically made of stone and engraved with a series of designs, these cylinders were rolled onto clay tablets, leaving a stamped impression of the design.

Starting in the mid-fourth millennium BCE, cylinder seals were used as part of an accounting system to track the production, storage, and transport of various consumer goods, particularly agricultural and textile products.

It is in this context that proto-cuneiform appeared: an archaic form of writing made up of hundreds of pictographic signs, more than half of which remain undeciphered to this day. Like cylinder seals, proto-cuneiform was used for accounting, though its use is primarily documented in southern Iraq.

"The close relationship between ancient sealing and the invention of writing in southwest Asia has long been recognised, but the relationship between specific seal images and sign shapes has hardly been explored," says Ferrara. "This was our starting question: did seal imagery contribute significantly to the invention of signs in the first writing in the region?"

To find an answer, the researchers systematically compared the designs on the cylinders with proto-cuneiform signs, looking for correlations that might reveal direct relationships in both graphic form and meaning.  

"We focused on seal imagery that originated before the invention of writing, while continuing to develop into the proto-literate period," add Kathryn Kelley and Mattia Cartolano, both researchers at the University of Bologna and co-authors of the study. "This approach allowed us to identify a series of designs related to the transport of textiles and pottery, which later evolved into corresponding proto-cuneiform signs."

This discovery reveals, for the first time, a direct link between the cylinder seal system and the invention of writing, offering new perspectives for studying the evolution of symbolic and writing systems.

"Our findings demonstrate that the designs engraved on cylinder seals are directly connected to the development of proto-cuneiform in southern Iraq," confirms Silvia Ferrara. "They also show how the meaning originally associated with these designs was integrated into a writing system."

The study was published in Antiquity under the title Seals and signs: tracing the origins of writing in ancient Southwest Asia. The authors are Kathryn Kelley, Mattia Cartolano, and Professor Silvia Ferrara from the Department of Classical Philology and Italian Studies at the University of Bologna.

Diagrams of proto-cuneiform signs and their precursors from pre-literate seals

Credit

Courtesy of CDLI - Cuneiform Digital Library Initiative

Journal

Antiquity

DOI

10.15184/aqy.2024.165 

Article Title

Seals and signs: tracing the origins of writing in ancient South-west Asia

Article Publication Date

5-Nov-2024

 

New study reveals racial disparities in breast cancer diagnosis and outcomes in Canada

Research from uOttawa, Stats Canada highlights importance of screening for individuals from age 40 who are typically diagnosed with breast cancer at younger ages

University of Ottawa

Canada’s current national screening guidelines for breast cancer are less appropriate for women of certain race and ethnicity groups since they are diagnosed at younger ages with more advanced stages of the disease. The new findings from a University of Ottawa research team underscore the urgent need to reevaluate screening guidelines to account for racial and ethnic differences and ensure equitable healthcare access, including earlier screening, to improve outcomes for all women. 

Breast cancer characteristics and outcomes in Canada related to race and ethnicity are not currently documented. This new study has found that Canadian women who did not identify as White had an earlier peak age of breast cancer diagnosis and higher proportions of cases diagnosed under age 50. They also have an earlier peak age of death, dying on average seven years earlier.

Key Findings

The study, which linked census data with the Canadian Cancer Registry to assess breast cancer cases, was conducted by a team of researchers led by Dr. Anna Wilkinson and Dr. Jean Seely along with Carmina Ng and Larry Ellison from Statistics Canada. 

Published in The Oncologist, key findings include:

• A Black woman in her 40s faces a breast cancer mortality rate that is 40% higher compared to White women of the same age group.
• First Nations and Métis women in their 60s face mortality rates 20% to 50% higher than White women of the same age groups, respectively.
• The peak age of breast cancer diagnosis was 65 for White women, compared to ages 42-60 for women of other race and ethnicity groups.
• About 1/3 of breast cancer cases were diagnosed before age 50 in ArabInuit, Korean, West Asian and multiethnic women compared to 16% in White women.
• White women have higher rates of hormone-positive breast cancer, a subtype associated with better outcomes, while Black women had double the proportion of aggressive triple-negative breast cancer, which has much poorer survival rates. (Five-year survival for stage III triple-negative breast cancer is only 74%, and just 7% for stage IV.)

Early Screening

“This study highlights the importance of screening starting at age 40 for individuals who are typically diagnosed with breast cancer at younger ages. Screening starting at age 50 systematically disadvantages women of race and ethnicity groups other than White, potentially leading to more advanced disease at diagnosis and, in the case of Black women, possibly higher mortality,” said lead author Dr. Wilkinson, Associate Professor in the Faculty of Medicine. 

“Moreover, elevated mortality rates among Metis and First Nations women mandate an examination of barriers to healthcare these women face across the cancer continuum—from screening to diagnosis to treatment.”

Addressing care gaps

Despite provincial advances – Ontario now includes women aged 40-49 in their organized screening program – national guidelines will continue to influence family physicians to recommend against screening when patients seek their guidance, according to researchers, potentially leading to missed opportunities for early detection among women of color.

The lead authors from uOttawa – whose previous research touches on screening guidelines and rising breast cancer rates – see updated cancer data collection as the best aid for understanding the underlying reasons for mortality disparities and to address gaps in cancer care.

---

Journal

The Oncologist

DOI

10.1093/oncolo/oyae283 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Breast cancer incidence and mortality, by age, stage and molecular subtypes, by race/ethnicity in Canada

Article Publication Date

2-Nov-2024

 

How animal tracking data can help preserve biodiversity

University of Michigan

 

image: 

A flammulated owl, Psiloscops flammeolus, is outfitted with an archival GPS unit.

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Credit: Scott Yanco

Today's ecologists have more data than ever before to help monitor and understand the world's biodiversity. Yet researchers are still working to get more detailed information to better combat declining animal populations that can eventually lead to species extinctions, says animal ecologist Scott Yanco of the University of Michigan.

Yanco, a research fellow at the U-M School for Environment and Sustainability, believes that change is on the horizon thanks to advances in animal tracking technology. Researchers affix these devices to individual animals to monitor their locations and other information over time. With these technologies, scientists are accumulating more detailed information throughout the lives of individual animals to understand the specific impacts of threats like pollution, climate change, and habitat loss and fragmentation.

Working with U-M evolutionary ecologist Brian Weeks and an international team, Yanco authored a new study highlighting the opportunity for animal tracking data to help usher in a new era of conservation.

Why is it important to study biodiversity?

Biodiversity—and the health of our biosphere more generally—is essential for human prosperity and well-being. Our biosphere is the basis by which we get our food, by which we get our water, by which we have the air to breathe. It is also the basis for much of our recreational activities and even wide swathes of our economy. Our biosphere is the foundation upon which human society is built. 

Often when we think of biodiverse places, we picture a rainforest in the Amazon or Southeast Asia—which are biodiverse, to be sure—but the biodiversity in your backyard matters, too.

Understanding what mechanisms are governing biodiversity is absolutely essential for us to develop policy and management and conservation actions so that we can try and prevent or mitigate the next pandemic, so that we can make sure that our crops are not subject to catastrophic failure, so that we can make sure that we're all drinking clean water and breathing clean air, and that we all have beautiful, restorative and important places to go and recreate and enjoy. Biodiversity is something that everybody should care about, even if they don't care about biodiversity. 

Can you share a brief history of how we've used animal tracking to monitor different species?

An animal tracking device is any device that we can put on an animal that allows us to record its position in time and space. Traditionally, we've done that by outfitting animals with simple markers. With birds, we use leg bands—most commonly little aluminum rings that we attach to their legs with a unique code. With mammals, we use things like collars and ear tags. 

However, to observe these individuals over time often requires finding and observing these animals multiple times, or even possibly even trying to recapture them multiple times. Having to recapture animals every single time we need to know their location means that we don't actually get information about them very often because doing so is time consuming, difficult work. As a result, the resolution of our data is quite coarse and it's hard to see things that are happening over short time scales.

More recently, there has been an absolute explosion in miniature electronic devices that can record an animal’s location. Much like the GPS built into your cell phone, these devices give us highly precise information about where an animal is on the planet and, increasingly, what it is doing. These new devices have created an avalanche of data revealing new details about the incredible movements animals are making and showing us the complex ways they interact with their environments. For many species, we can now do this sort of tracking over global extents and for long periods of time.

These new tools create a unique opportunity to study not just animal behavior, but also the processes that affect things like reproduction or mortality—exactly the types of things we need to know if we want to understand what is driving the global loss of biodiversity.

How can animal tracking be used to address biodiversity loss?

We do a decent job of monitoring population levels for many species—in many cases, we know when populations go up and down. What we're missing about these species are the specifics causes that lead these populations to go up and down. And by causes, I don't mean general understandings like, "Climate change is bad for Species X." Rather, precisely how does that process work—what exactly is climate change doing? Is there a place where we can intervene?

For example, it's one thing to say, "Habitat fragmentation did it." But it's more informative if we can say, "Habitat fragmentation in this one place puts animals into a body condition that makes them less likely to survive migration, and that results in mortalities in a specific area." In that case, we have a whole chain of events that we can look at and use to design on-the-ground interventions that can make a difference for that species. 

We know at a broad scale that things like disease, pollution, invasive species, climate change, habitat loss, direct exploitation, or harvesting animals, have an impact. But we can't just say, "Stop doing all that." Instead we need to find ways to make targeted recommendations that we know will have a positive effect on wildlife populations. By getting really detailed information about the exact drivers of population declines, we can be very specific about how we might modify human activities to reverse those declines.  Doing it that way might allow us to achieve conservation outcomes while minimizing the impact to humans—that's a win-win for all parties.

Because animal tracking gives us such a detailed view into animals' lives, we have this new opportunity to generate exactly the sort of insights we so desperately need. It allows us to study species that were previously hard to observe, to track outcomes over huge parts of the globe and to do so with incredible precision.  

What are some of the modern and emerging animal tracking technologies you're excited about?

The ones that we all love to work with—if our study system or species can support them—are GPS units just like in your telephone. They can sometimes even use cell networks or satellites to send the data to us without researchers ever needing to relocate the animal. Now, if you're putting a device like this on an elk or an elephant, it doesn't need to be much smaller than your telephone. But we always try to minimize how much weight we put on an animal and, as the animals get smaller, the devices we use need to be miniaturized. 

For the kinds of birds that I often work with, they're simply too light to carry that kind of GPS package. So we're working with tags that can record data, but can't always send it to us and that's a really active area in development—and there are many emerging solutions to this problem. One example is a system called ICARUS that's moving toward smaller tags and using space-based satellites for data uploads. 

Increasingly, we also see auxiliary sensors included with these trackers, with which we can measure other things like temperature, relative humidity and air pressure. There are mortality switches that can send a signal when it thinks the animal has been motionless for too long and maybe has died. There are tags that you can implant into deer and elk to understand if they've given birth. 

For example, I have a new paper where one of my collaborators surgically implanted a heart rate monitor and a body temperature monitor inside these little blackbirds. We could measure their heart rate every 30 minutes for almost a whole year and understand the dynamics of how much energy they were spending, how they prepared for migration, and how they thermoregulated in different environments.

There has really been a tremendous explosion in the types of technologies that we've been seeing. And, again, this level of detail gives us a new way to understand how human activities are contributing to species extinctions so that we can reverse those processes.

As part of a University of Michigan-led project, researchers are tagging a juvenile tree swallow with a small Motus automated radio-telemetry tag on its back.

Credit

Scott Yanco

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Journal

Trends in Ecology & Evolution

DOI

10.1016/j.tree.2024.09.008 

Article Title

Tracking individual animals can reveal the mechanisms of species loss

Article Publication Date

5-Nov-2024

 

At the top of the world, lead pollution reaches even pristine glaciers

Study finds human environmental impact more radical than expected

Ohio State University

COLUMBUS, Ohio – Human activities have led to the pollution of some of the remotest places in the world, a new study shows. 

By examining ice cores taken from the Guliya ice cap in northwestern Tibet, researchers found that by measuring lead isotopes in dust-filled samples, they could detect a clear change in lead source levels present in the environment long after the Industrial Revolution. 

While increases in the amount of lead could be found in ice core samples dated to the beginning of the Industrial Revolution, a significant change in its origin was noted beginning in 1974, when regulatory agencies in the U.S. began to institute strong emissions policies to curb dangerous overexposure to the metal. Though this caused a decrease in some types of gasoline use in some countries, other sources of lead emissions peaked later, said Roxana Sierra-Hernandez, lead author of the study and a senior research associate at The Ohio State University’s Byrd Polar and Climate Research Center. 

“Our lead isotope samples date to about 36,000 years ago, a time when we know that no civilizations at the time were using lead – meaning that much of what we found is natural,” she said. “Now with this work, we can pinpoint anthropogenic lead and when they left a mark in the region.”

The study was published recently in the journal Communications Earth & Environment. 

Millions of people rely on the glaciers in the Tibetan Plateau for life-sustaining water, but as global warming causes glaciers to retreat, those communities are put in jeopardy due to reduced water levels. What’s more, as glaciers continue to melt, the pollutants preserved inside them will also escape, said Sierra-Hernandez. 

“Depending on the amount of pollution there is in the environment, it sinks into these glaciers,” she said. “If a glacier melts, that source of pollution can leak into nearby rivers.” 

While small quantities of lead do originate from beneath the Earth’s crust, the bigger issue is lead put into the environment through human activity, she said. Prolonged exposure to the heavy metal can be toxic to humans, both when ingested or inhaled through contaminated food, water or air. It has been known to lead to a wide variety of health issues, including cancer, cardiovascular disease and fertility issues. 

With more accurate data on what constitutes a natural lead baseline, researchers can get a better handle on how drastically humans have affected the environment and better prepare for these consequences, according to the research. 

What also sets this study apart, said Sierra-Hernandez, is that the instruments and models the research team used were sensitive enough to discern the type of pollution the lead came from. They found that up until 2007, Chinese gasoline was the main source of the lead before those emissions decreased and emissions from coal and lead-zinc ores increased. 

Overall, their work emphasizes a huge change in lead sources during the last few centuries, and offers a glimpse into how local pollution distributes globally, even to faraway glacial regions. 

It’s an issue that likely won’t be solved by one country alone, noted the study. “Politicians need to be conscious enough to see that lead is still a concern and make policies that avoid emitting more of it, whether it’s from sources of coal or gasoline,” said Sierra-Hernandez.

Additionally, since lead isotopes can act like a fingerprint for unique chemical signatures,  researchers can use them to track and investigate sources of pollution, opening a path for similar studies to analyze and compare polluted ice core samples from other glaciers around the world, said Sierra-Hernandez. 

“Future studies can build on this study to compare modern and ancient pollution trends and better identify sources due to human activities,” she said. “It’s important to do more lead isotope studies. It’s hard and it’s time-consuming, but there’s so much to learn.”

Other co-authors include Elizabeth M. Griffith and Lonnie G. Thompson from Ohio State as well as Franco Marcantonio from Texas A&M University.

#

Contact: Roxana Sierra-Hernandez, Sierra-Hernandez.1@osu.edu

Written by: Tatyana Woodall, Woodall.52@osu.ed

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Journal

Communications Earth & Environment

DOI

10.1038/s43247-024-01724-w 

Article Title

Sources of lead in a Tibetan glacier since the Stone Age