New approach predicts disease transmission among wildlife and humans

Using machine learning, researchers can forecast outbreaks of pathogens such as coronavirus and monkeypox

Peer-Reviewed Publication

UNIVERSITY OF SOUTH FLORIDA

TAMPA, Fla. (Sept. 1, 2022) – The rate that emerging wildlife diseases infect humans has steadily increased over the last three decades. Viruses, such as the global coronavirus pandemic and recent monkeypox outbreak, have heightened the urgent need for disease ecology tools to forecast when and where disease outbreaks are likely.

A University of South Florida assistant professor helped develop a methodology that will do just that – predict disease transmission from wildlife to humans, from one wildlife species to another and determine who is at risk of infection.

The methodology is a machine-learning approach that identifies the influence of variables, such as location and climate, on known pathogens. Using only small amounts of information, the system is able to identify community hot spots at risk of infection on both global and local scales.

“Our main goal is to develop this tool for preventive measures,” said co-principal investigator Diego Santiago-Alarcon, a USF assistant professor of integrative biology. “It’s difficult to have an all-purpose methodology that can be used to predict infections across all the diverse parasite systems, but with this research, we contribute to achieving that goal.”

With help from researchers at the Universiad Veracruzana and Instituto de Ecologia, located in Mexico, Santiago-Alarcon examined three host-pathogen systems – avian malaria, birds with West Nile virus and bats with coronavirus – to test the reliability and accuracy of the models generated by the methodology.

The team found that for the three systems, the species most frequently infected was not necessarily the most susceptible to the disease. To better pinpoint hosts with higher risk of infection, it was important to identify relevant factors, such as climate and evolutionary relationships.

By integrating geographic, environmental and evolutionary development variables, the researchers identified host species that have previously not been recorded as infected by the parasite under study, providing a way to identify susceptible species and eventually mitigate pathogen risk.

“We feel confident that the methodology is successful, and it can be applied widely to many host-pathogen systems,” Santiago-Alarcon said. “We now enter into a phase of improvement and refinement.”

The results, published in the Proceedings of the National Academy of Sciences, prove the methodology is able to provide reliable global predictions for the studied host–pathogen systems, even when using a small amount of information. This new approach will help direct infectious disease surveillance and field efforts, providing a cost-effective strategy to better determine where to invest limited disease resources.

Predicting what kind of pathogen will produce the next medical or veterinary infection is challenging, but necessary. As the rate of human impact on natural environments increases, opportunity for novel diseases will continue to rise.

“Humanity, and indeed biodiversity in general, are experiencing more and more infectious disease challenges as a result of our incursion and destruction of the natural order worldwide through things like deforestation, global trade and climate change,” said Andrés Lira-Noriega, research fellow at the Instituto de Ecologia. “This imposes the need of having tools like the one we are publishing to help us predict where new threats in terms of new pathogens and their reservoirs may occur or arise.”

The team plans to continue their research to further test the methodology on additional host-pathogen systems and extend the study of disease transmission to predict future outbreaks. The goal is to make the tool easily accessible through an app for the scientific community by the end of 2022.

About the University of South Florida

The University of South Florida, a high-impact global research university dedicated to student success, generates an annual economic impact of more than $6 billion. Over the past 10 years, no other public university in the country has risen faster in U.S. News and World Report’s national university rankings than USF. Serving more than 50,000 students on campuses in Tampa, St. Petersburg and Sarasota-Manatee, USF is designated as a Preeminent State Research University by the Florida Board of Governors, placing it in the most elite category among the state’s 12 public universities. USF has earned widespread national recognition for its success graduating under-represented minority and limited-income students at rates equal to or higher than white and higher income students. USF is a member of the American Athletic Conference. Learn more at www.usf.edu.

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2122851119 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Wildlife susceptibility to infectious diseases at global scales

Individual risk-factor data could help predict the next Ebola outbreak, new study shows

Researchers confirm a relationship between social, economic and demographic factors and the propensity for individuals to engage in behaviors that expose them to Ebola spillover

Peer-Reviewed Publication

LEHIGH UNIVERSITY

 

IMAGE: JAVIER BUCETA (FRONT LEFT), A FACULTY MEMBER AT THE INSTITUTE FOR INTEGRATIVE SYSTEMS BIOLOGY, AND PAOLO BOCCHINI (FRONT RIGHT), PROFESSOR OF CIVIL AND ENVIRONMENTAL ENGINEERING AT LEHIGH UNIVERSITY. view more 

CREDIT: STEPHANIE VETO/LEHIGH UNIVERSITY

Several years ago, a team of scientists at Lehigh University developed a predictive model to accurately forecast Ebola outbreaks based on climate-driven bat migration. Ebola is a serious and sometimes-deadly infectious disease that is zoonotic, or enters a human population via interaction with animals. It is widely believed that the source of the 2014 Ebola outbreak in West Africa, which killed more than 11,000 people, was human interaction with bats.

Now members of the team have examined how social and economic factors, such as level of education and general knowledge of Ebola, might contribute to “high-risk behaviors” that may bring individuals into contact with potentially infected animals. A focus on geographical locations with high concentrations of individuals at high-risk could help public health officials better target prevention and education resources.  

“We created a survey that combined the collection of social, demographic and economic data with questions related to general knowledge of Ebola transmission and potentially high-risk behaviors,” says Paolo Bocchini, professor of civil and environmental engineering at Lehigh and one of the study’s leaders. “Our results show that it is indeed possible to calibrate a model to predict, with a reasonable level of accuracy, the propensity of an individual to engage in high-risk behaviors.”

For example, the team’s data and analyses suggested Kailahun, a town in Eastern Sierra Leone, and Kambia in the northern part of the country, as the rural districts in the country with the highest likelihood of infection spillover, based on individual risk factors accurately identifying the location, Kailahun, where the 2014 Ebola epidemic is believed to have originated.

The results are detailed in a paper “Estimation of Ebola’s spillover infection exposure in Sierra Leone based on sociodemographic and economic factors” which will soon be published in PLOS ONE. Additional authors include: Lehigh University graduate student Sena Mursel, undergraduates Nathaniel Alter, Lindsay Slavit and Anna Smith; and Javier Buceta, a faculty member at the Institute for Integrative Systems Biology in Valencia, Spain.

Among the findings: young adults (ages between 18-34) and adults (ages between 34 - 50) were most at risk in the population they studied. This group constituted 77% of the investigated sample, but 86% of the respondents were at risk. In addition, those with agricultural jobs were among the most at risk: 50% of the study respondents have an agriculture-related occupation, but represent 79% of respondents at risk

“We confirmed a relationship between social, economic and demographic factors and the propensity for individuals to engage in behaviors that expose them to Ebola spillover,” says Bocchini. “We also calibrated a preliminary model that quantifies this relationship.”

The authors say these results point to the need for a holistic approach for any model seeking to accurately predict disease outbreaks. Their findings may also be useful for population health officials, who may be able to use such models to better focus scarce resources.

“One has to look at the big picture,” says Bocchini. “We collected satellite images that showed the evolution of enviro-climatic data and combined them with ecological models and random field models to capture the spatial and temporal fluctuations of natural resources and the resulting continent-wide migrations of infected animal carriers. We also studied the human population’s social, economic, demographic and behavioral characteristics, integrating everything to obtain our predictions.”

“Only this broad perspective and interdisciplinary approach can truly capture these dynamics, and with this line of research we are proving that it works,” adds Bocchini.

“In the end, the conclusions of our study are not that surprising: greater economic means, more education, and access to information are key factors to reduce health-related high-risk behaviors” said Buceta. “Indeed, some of these factors have been related with what is known as the ‘health poverty trap.’ Our study and methodology show how quantitative analyses concerning individual, rather than aggregated, data can be used to identify these factors.”   

To collect data for their study, Bocchini and Buceta traveled to Sierra Leone with a delegation of undergraduate students from Lehigh with support from the National Institutes of Health, Lehigh’s Office of Creative Inquiry and in collaboration with nonprofit World Hope International. The assistance of two local translators was critical to the team’s success in administering their survey door-to-door. The students who worked on the project were part of Lehigh’s Global Social Impact Fellowship program which engages undergraduate and graduate students in work focused on addressing sustainable development challenges in low- and middle-income countries. 

“This is precisely the kind of ambitious interdisciplinary project with tremendous potential for social impact that we want Lehigh students to engage with through the Global Social Impact Fellowship,” says Khanjan Mehta, Vice Provost for Creative Inquiry at Lehigh. “Students from various disciplines across Lehigh had the opportunity to contribute to this work under Dr. Bocchini and Dr. Buceta’s leadership.”

The team’s promising results are a strong argument for broader data collection and they are in conversations with Statistics Sierra Leone, the country’s census bureau, to perform a nationwide version of their study.

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JOURNAL

PLoS ONE

DOI

10.1371/journal.pone.0271886 

ARTICLE TITLE

Estimation of Ebola's spillover infection exposure in Sierra Leone based on sociodemographic and economic factors

ARTICLE PUBLICATION DATE

1-Sep-2022

Recent advances in air quality research

Peer-Reviewed Publication

AMERICAN CHEMICAL SOCIETY

A deep breath of fresh air can feel restorative. However, if the air is polluted by airborne particles or volatile compounds, then breathing it in can be an unpleasant, or potentially harmful, experience. Below are some recent papers published in ACS journals that report insights into the sources and potential exposure risks of particulate matter and gases that affect air quality indoors and outdoors. Reporters can request free access to these papers by emailing newsroom@acs.org.

“Plastic Burning Impacts on Atmospheric Fine Particulate Matter at Urban and Rural Sites in the USA and Bangladesh”
ACS Environmental Au
June 9, 2022
Burning garbage, particularly plastic waste, releases particulate matter and toxic gases into the air. Here, researchers measured a molecular tracer for burned plastic in airborne particles collected at urban and rural locations in the U.S. and Bangladesh. They found that plastic burning was a minor source of particulate matter in the U.S., but in Dhaka, Bangladesh, the country’s capital, it contributed up to 15% of the particulate matter.

“Gas- and Particle-Phase Amide Emissions from Cooking: Mechanisms and Air Quality Impacts”
Environmental Science & Technology
June 7, 2022
In this study, researchers conducted lab experiments to investigate the compounds released by the high-temperature cooking of meats in oil. They heated amino acids, the building blocks of meat proteins, and different oils at 347 to 419 F. They found that amides, including some that are harmful to humans, were in both vapors and airborne particles. This food preparation method could contribute to poorer indoor and outdoor air quality and potential health risks if inhaled, the researchers say.

“Molecular Characterization of Organosulfate-Dominated Aerosols over Agricultural Fields from the Southern Great Plains by High-Resolution Mass Spectrometry”
ACS Earth and Space Chemistry
May 10, 2022
Here, researchers examined the molecular composition of aerosols — extremely small droplets — above crop fields, using high-resolution mass spectrometry. The aerosol composition followed diurnal cycles and was strongly affected by the wind’s direction, which episodically brought in urban emissions. The researchers say these results could have implications for local weather patterns, crop growth and human health.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

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Study of people exposed to air pollution reveals greater effects on females than males

Reports and Proceedings

EUROPEAN LUNG FOUNDATION

 NEWS RELEASE 1-SEP-2022

The impact of breathing diesel exhaust fumes may be more severe for females than males, according to new research that will be presented at the European Respiratory Society International Congress in Barcelona, Spain [1].

Researchers looked for changes in people’s blood brought about by exposure to diesel exhaust. In both females and males, they found changes in components of the blood related to inflammation, infection and cardiovascular disease, but they found more changes in females than males.

The research was presented by Dr Hemshekhar Mahadevappa, from the University of Manitoba, Winnipeg, Canada and was a collaboration between two research groups led by Professor Neeloffer Mookherjee at the University of Manitoba and Professor Chris Carlsten at the University of British Columbia, Vancouver, Canada. Dr Mahadevappa told the Congress: “We already know that there are sex differences in lung diseases such as asthma and respiratory infections. Our previous research showed that breathing diesel exhaust creates inflammation in the lungs and has an impact on how the body deals with respiratory infections. In this study, we wanted to look for any effects in the blood and how these differ in females and males.”

The study involved ten volunteers, five female and five male, who were all healthy non-smokers. Each volunteer spent four hours breathing filtered air and four hours breathing air containing diesel exhaust fumes at three different concentrations – 20, 50 and 150 micrograms of fine particulate matter (PM2.5) per cubic metre – with a four-week break in between each exposure. The current European Union annual limit value for PM2.5 is 25 micrograms per cubic metre, but much higher peaks are common in many cities.

Volunteers donated blood samples 24 hours after each exposure and the researchers made detailed examinations of the volunteers’ blood plasma. Plasma is the liquid component of the blood that carries blood cells as well as hundreds of proteins and other molecules around the body. Using a well-established analysis technology called liquid chromatography–mass spectrometry, the researchers looked for changes in the levels of different proteins following exposure to diesel exhaust and compared the changes in females and males.

Comparing the plasma samples, the researchers found levels of 90 proteins that were distinctly different between female and male volunteers following exposure to diesel exhaust. Among the proteins that differed between females and males, were some that are known to play a role in inflammation, damage repair, blood clotting, cardiovascular disease and the immune system. Some of these differences became clearer when volunteers were exposed to the higher levels of diesel exhaust.

Professor Mookherjee explained: “These are preliminary findings, however they show that exposure to diesel exhaust has different effects in female bodies compared to male and that could indicate that air pollution is more dangerous for females than males.

“This is important as respiratory diseases such as asthma are known to effect females and males differently, with females more likely to suffer severe asthma that does not respond to treatments. Therefore, we need to know a lot more about how females and males respond to air pollution and what this means for preventing, diagnosing and treating their respiratory disease.”

The researchers plan to continue studying the functions of these proteins to better understand their role in the difference between female and male immune responses.

Professor Zorana Andersen from the University of Copenhagen, Denmark, is Chair of the European Respiratory Society Environment and Health Committee and was not involved in the research. She said: “We know that exposure to air pollution, especially diesel exhaust, is a major risk factor in diseases such as asthma and chronic obstructive pulmonary disease. There is very little we can do as individuals to avoid beathing polluted air, so we need governments to set and enforce limits on air pollutants.

“We also need to understand how and why air pollution contributes to poor health. This study offers some important insight into how the body reacts to diesel exhaust and how that may differ between females and males.”

SEE  LA REVUE GAUCHE - Left Comment: Search results for LUNG CANCER 

Rethinking indoor air chemistry

People generate their own oxidation field and change the indoor air chemistry around them

Peer-Reviewed Publication

MAX PLANCK INSTITUTE FOR CHEMISTRY

 

IMAGE: COMPUTER MODELLING OF THE OH REACTIVITY (LEFT) AND OH CONCENTRATION (RIGHT) AROUND HUMAN BODIES IN A TYPICAL INDOOR SITUATION WHILE PEOPLE SITTING AROUND A TABLE view more 

CREDIT: UC IRVINE

People typically spend 90 percent of their lives inside, at home, at work, or in transport. Within these enclosed spaces, occupants are exposed to a multitude of chemicals from various sources, including outdoor pollutants penetrating indoors, gaseous emissions from building materials and furnishings, and products of our own activities such as cooking and cleaning. In addition, we are ourselves potent mobile emission sources of chemicals that enter the indoor air from our breath and skin.

But how do the chemicals disappear again? In the atmosphere outdoors, this happens to a certain extent naturally by itself, when it rains and through chemical oxidation. Hydroxyl (OH) radicals are largely responsible for this chemical cleaning. These very reactive molecules are also called the detergents of the atmosphere and they are primarily formed when UV light from the sun interacts with ozone and water vapor.

Indoors, on the other hand, the air is of course far less affected by direct sunlight and rain. Since UV rays are largely filtered out by glass windows it has been generally assumed that the concentration of OH radicals is substantially lower indoors than outdoors and that ozone, leaking in from outdoors, is the major oxidant of indoor airborne chemical pollutants.

OH radicals are formed from ozone and skin oils

However, now it has been discovered that high levels of OH radicals can be generated indoors, simply due to the presence of people and ozone. This has been shown by a team led by the Max Planck Institute for Chemistry in cooperation with researchers from the USA and Denmark.

"The discovery that we humans are not only a source of reactive chemicals, but we are also able to transform these chemicals ourselves was very surprising to us," says Nora Zannoni, first author of the study published in the research magazine Science, and now at the Institute of Atmospheric Sciences and Climate in Bologna, Italy. "The strength and shape of the oxidation field are determined by how much ozone is present, where it infiltrates, and how the ventilation of the indoor space is configured," adds the scientist from Jonathan Williams' team. The levels the scientists found were even comparable to outside daytime OH concentrations levels.

The oxidation field is generated by the reaction of ozone with oils and fats on our skin, especially the unsaturated triterpene squalene, which constitutes about 10 percent of the skin lipids that protect our skin and keep it supple. The reaction releases a host of gas phase chemicals containing double bonds that react further in the air with ozone to generate substantial levels of OH radicals. These squalene degradation products were characterized and quantified individually using Proton Transfer reaction Mass Spectrometry and fast gas chromatograph-mass spectrometry systems. In addition, the total OH reactivity was determined in parallel enabling the OH levels to be quantified empirically.

The experiments were conducted at the Technical University of Denmark (DTU) in Copenhagen. Four test subjects stayed in a special climate-controlled chamber under standardized conditions. Ozone was added to the chamber air inflow in a quantity that was not harmful to humans but representative of higher indoor levels. The team determined the OH values before and during the volunteers' stay both with and without ozone present.

In order to understand how the human-generated OH field looked like in space and time during the experiments, results from a detailed multiphase chemical kinetic model from the University of California, Irvine were combined with a computational fluid dynamics model from Pennsylvania State University, both based in the USA. After validating the models against the experimental results, the modeling team examined how the human-generated OH field varied under different conditions of ventilation and ozone, beyond those tested in the laboratory. From the results, it was clear that the OH radicals were present, abundant, and forming strong spatial gradients.

“Our modeling team is the first and currently the only group that can integrate chemical processes between the skin and indoor air, from molecular scales to room scales,” said Manabu Shiraiwa, a professor at UC Irvine who led the modeling part of the new work. “The model makes sense of the measurements — why OH is generated from the reaction with the skin.”

Shiraiwa added that there remain unanswered questions, like the way humidity levels impact the reactions the team traced. “I think this study opens up a new avenue for indoor air research,” he said.

Adapt test methods for furniture and building materials

"We need to rethink indoor chemistry in occupied spaces because the oxidation field we create will transform many of the chemicals in our immediate vicinity. OH can oxidize many more species than ozone, creating a multitude of products directly in our breathing zone with as yet unknown health impacts”. This oxidation field will also impact the chemical signals we emit and receive," says project leader Jonathan Williams, “and possibly help explain the recent finding that our sense of smell is generally more sensitive to molecules that react faster with OH.”

The new finding also has implications for our health: Currently, chemical emissions of many materials and furnishings are being tested in isolation before they are approved for sale. However, it would be advisable to also conduct tests in the presence of people and ozone, says atmospheric chemist Williams. This is because oxidation processes can lead to the generation of respiratory irritants such as 4-oxopentanal (4-OPA) and other OH radical-generated oxygenated species, and small particles in the immediate vicinity of the respiratory tract. These can have adverse effects, especially in children and the infirm.

These findings are part of the project ICHEAR (Indoor Chemical Human Emissions and Reactivity Project) which brought together a group of collaborating international scientists from Denmark (DTU), the USA (Rutgers University), and Germany (MPI). The modeling was part of the MOCCIE project based at the University of California Irvine and the Pennsylvania State University. Both projects were funded by grants from the A. P. Sloan foundation.

CAPTION

Not visible, but measurable: an oxidation field is generated around each person in the stainless steel climate chamber at the Technical University of Denmark.

CREDIT

 

Original publication

The Human Oxidation Field
Nora Zannoni, Pascale S. J. Lakey, Youngbo Won, Manabu Shiraiwa, Donghyun Rim, Charles J. Weschler, Nijing Wang, Lisa Ernle, Mengze Li, Gabriel Bekö, Pawel Wargocki, Jonathan Williams
Science, 1 September 2022
Doi: 10.1126/science.abn0340

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JOURNAL

Science

DOI

10.1126/science.abn0340 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The Human Oxidation Field

ARTICLE PUBLICATION DATE

2-Sep-2022

The human body produces hydroxyl radicals when exposed to ozone in indoor environments

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

The human body’s exposure to ozone in indoor spaces generates highly reactive hydroxyl (OH), radicals which are largely responsible for the oxidation of most pollutant gases, researchers report. The findings have implications for our understanding of the role of humans in indoor air chemistry and quality. “[The authors] observed that the human body interacts with the indoor environment in an analogous manner to how Earth interacts with the atmosphere,” write Coralie Schoemaecker and Nicola Carslaw in a related Perspective. “Both the human body and Earth are chemical reactors, consuming or producing oxidants and oxidized species in their surrounding atmospheres.” The vast majority of humans spend most of their time indoors – whether at their home or workplace or while traveling between the two – and are exposed to a number of chemicals from various sources, including outdoor pollutants that find their way inside, gaseous emissions from building materials and furnishings, and products of activities such as cooking and cleaning. Moreover, the human body is also a potent mobile source of emissions. Chemical removal of gas-phase pollutants in outside air during daytime is mostly driven by the production of OH radicals, which are formed primarily by the photolysis of ozone by ultraviolet sunlight. However, indoor air quality is much less impacted by this process, as glass windows largely filter out ultraviolet light. While research has shown that some OH radicals can be generated by other means in indoor environments, few studies have evaluated the chemical influence human bodies in these environments. Through a series of experiments, Nora Zannoni and colleagues found that high concentrations of OH radicals are generated when people were exposed to different concentrations of ozone within a climate-controlled, stainless-steel chamber. According to Zannoni et al., squalene in skin oil reacted with to produce 6-methyl-5-hepten-2-one (6-MHO), which was key to establishing this human-induced oxidation field. What’s more, they found that isoprene from human breath and products of its interaction with OH also react with ozone to produce more OH radicals, suggesting that humans are a net source of reactive oxidants indoors.

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JOURNAL

Science

DOI

10.1126/science.abn0340 

ARTICLE TITLE

The human oxidation field

ARTICLE PUBLICATION DATE

2-Sep-2022

Toxins in old toys an obstacle for circular economy

Peer-Reviewed Publication

UNIVERSITY OF GOTHENBURG

 

IMAGE: MANY OF THE OLDER TOYS CONTAINED TOXINS. view more 

CREDIT: NONE

Letting children play with hand-me-down plastic toys could constitute a health risk. When researchers at the University of Gothenburg tested a large number of old toys and dress-up items made of plastic, 84 per cent of the items were found to contain toxins that can disrupt growth and development and reproductive capacities in children. These toxins are an obstacle for the circular economy in the future involving reuse and recycling, the researchers explain.

The current use-and-discard behaviour is wasteful with resources and a drain on the Earth’s finite resources. In 2021, the European Parliament adopted a Circular Economy Action Plan. It encourages the re-use, repair and recycling of products and materials. But the question is whether all products are good to reuse again?

Researchers from the University of Gothenburg have recently published an article in the Journal of Hazardous Materials Advances which shows that old toys and dress-up items may contain toxic chemicals that can cause cancer, damage DNA or disrupt the future reproductive capacities of children.

Toxic chemicals in most old toys

The hazardous chemicals that were discovered included phthalates and short chain chlorinated paraffins used as plasticizers and flame retardants in toys.  

Professor Bethanie Carney Almroth at the University of Gothenburg conducts research on the environmental impact of plastics and plastic-related chemicals, and has led the research study conducted at the interdisciplinary Centre for Future Chemical Risk Assessment and Management Strategies (FRAM). For the study, researchers selected 157 different toys, new and old, and measured their chemical content.

The study showed that most of the older toys and items (84 per cent) contained quantities of chemicals that exceed current legal limits. A total of 30 per cent of the newer toys and items also exceeded the legal limits. By far however, the older toys were significantly worse.

“The concentrations of toxic substances were significantly higher in the older items. For example, many of the old balls were found to have concentrations of phthalates totalling more than 40 per cent of the toy’s weight, which is 400 times over the legal limit,” says Bethanie Carney Almroth.

Toxins an obstacle to a circular economy

EU legislation on the chemical content of toys, known as the Toy Safety Directive, regulates the permissible quantities of a number of chemical substances found in toys in an attempt to protect the health and safety of children. At present, the permissible limit values for new toys under the Toy Safety Directive are 0.1 per cent by weight for phthalates and 0.15 per cent by weight for short chain chlorinated paraffins.

“The study indicates that reuse and recycling is not always automatically a good thing. The transition to a more circular economy requires bans and other policy measures that get rid of hazardous chemicals from plastic and other materials. Although the Toy Safety Directive has been crucial in reducing the incidence of hazardous chemicals in toys, it has only been applicable to new toys, not old ones,” explains Daniel Slunge, Environmental Economist at the University of Gothenburg. 

Facts: FRAM

FRAM is the Swedish acronym for the University of Gothenburg’s interdisciplinary Centre for Future Chemical Risk Assessment and Management Strategies. FRAM brings together expertise from the fields of science, economics, law and political science to garner support for a precautionary principle when assessing and managing risks linked to how chemical compounds impact human health and the environment.

Read the scientific journal article: Circular economy could expose children to hazardous phthalates and chlorinated paraffins via old toys and childcare articles

Links for further reading:

What counts as a toy? Read more about the Toy Safety Directive (in Swedish only)

Read more about toxic chemicals that the Swedish Chemicals Agency wants to phase out

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DOI

10.1016/j.hazadv.2022.100107 

METHOD OF RESEARCH

Content analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Circular economy could expose children to hazardous phthalates and chlorinated paraffins via old toys and childcare articles

Global analysis identifies at-risk forests

Peer-Reviewed Publication

UNIVERSITY OF UTAH

 

IMAGE: WILDFIRE AT LICK CREEK, UMATILLA NATIONAL FOREST, OREGON, UNITED STATES. view more 

CREDIT: BRENDAN O'REILLY/U.S. FOREST SERVICE

Forests are engaged in a delicate, deadly dance with climate change, sucking carbon dioxide out of the air with billions of leafy straws and hosting abundant biodiversity, as long as climate change, with its droughts, wildfires and ecosystem shifts, doesn’t kill them first.

In a study published in Science William Anderegg, inaugural director of the University of Utah’s Wilkes Center for Climate Science and Policy, and colleagues quantify the risk to forests from climate change along three dimensions: carbon storage, biodiversity and forest loss from disturbance, such as fire or drought. The results show forests in some regions experiencing clear and consistent risks. In other regions, the risk profile is less clear, because different approaches that account for disparate aspects of climate risk yield diverging answers.

“Large uncertainty in most regions highlights that there's a lot more scientific study that's urgently needed,” Anderegg says.

An international team

Anderegg assembled a team including researchers from the United Kingdom, Germany, Portugal and Sweden.

“I had met some of these folks before,” he says, “and had read many of their papers. In undertaking a large, synthetic analysis like this, I contacted them to ask if they wanted to be involved in a global analysis and provide their expertise and data.”

Their task was formidable –assess climate risks to the world’s forests, which span continents and climes and host tremendous biodiversity while storing an immense amount of carbon. Researchers had previously attempted to quantify risks to forests using vegetation models, relationships between climate and forest attributes and climate effects on forest loss.

“These approaches have different inherent strengths and weaknesses,” the team writes, “but a synthesis of approaches at a global scale is lacking.” Each of the previous approaches investigated one dimension of climate risk: carbon storage, biodiversity, and risk of forest loss. For their new analysis, the team went after all three.

Three dimensions of risk

“These dimensions of risk are all important and, in many cases, complementary. They capture different aspects of forests resilience or vulnerability,” Anderegg says.  

Carbon storage: Forests absorb about a quarter of the carbon dioxide that’s emitted into the atmosphere, so they play a critically important role in buffering the planet from the effects of rising atmospheric carbon dioxide. The team leveraged output from dozens of different climate models and vegetation models simulating how different plant and tree types respond to different climates. They then compared the recent past climate (1995-2014) with the end of the 21st century (2081-2100) in scenarios of both high and low carbon emissions.

On average, the models showed global gains in carbon storage by the end of the century, although with large disagreements and uncertainty across the different climate-vegetation models. But zooming in to regional forests and taking into account models that forecast carbon loss and changes in vegetation, the researchers found higher risk of carbon loss in southern boreal (just south of the Arctic) forests and the drier regions of the Amazon and African tropics.

Biodiversity: Unsurprisingly, the researchers found that the highest risk of ecosystems shifting from one “life zone” to another due to climate change could be found at the current boundaries of biomes – at the current transition between temperate and boreal forests, for example. The models the researchers worked from described changes in ecosystems as a whole and not species individually, but the results suggested that forests of the boreal regions and western North America faced the greatest risk of biodiversity loss.

Disturbance: Finally, the authors looked at the risk of “stand-replacing disturbances,” or events like drought, fire or insect damage that could wipe out swaths of forest. Using satellite data and observations of stand-replacing disturbances between 2002 and 2014, the researchers then forecast into the future using projected future temperatures and precipitation to see how much more frequent these events might become. The boreal forests, again, face high risk under these conditions, as well as the tropics.  

“Forests store an immense amount of carbon and slow the pace of climate change,” Anderegg says. “They harbor the vast majority of Earth's biodiversity. And they can be quite vulnerable to disturbances like severe fire or drought. Thus, it's important to consider each of these aspects and dimensions when thinking about the future of Earth's forests in a rapidly changing climate.”

Future needs

Anderegg was surprised that the spatial patterns of high risk didn’t overlap more across the different dimensions.
“They capture different aspects of forests' responses,” he says, “so they wouldn't likely be identical, but I did expect some similar patterns and correlations.”

Models can only be as good as the basis of scientific understanding and data on which they’re built and this study, the researchers write, exposes significant understanding and data gaps that may contribute to the inconsistent results. Global models of biodiversity, for example, don’t incorporate dynamics of growth and mortality, or include the effects of rising CO2 directly on species. And models of forest disturbance don’t include regrowth or species turnover.

“If forests are tapped to play an important role in climate mitigation,” the authors write, “an enormous scientific effort is needed to better shed light on when and where forests will be resilient to climate change in the 21st century.”

Key next steps, Anderegg says, are improving models of forest disturbance, studying the resilience of forests after disturbance, and improving large-scale ecosystem models.

The recently-launched Wilkes Center for Climate Science and Policy at the University of Utah aims to provide cutting-edge science and tools for decision-makers in the US and across the globe. For this study, the authors built a visualization tool of the results for stakeholders and decision-makers.  

Despite uncertainty in the results, western North America seems to have a consistently high risk to forests. Preserving these forests, he says, requires action.

“First we have to realize that the quicker we tackle climate change, the lower the risks in the West will be,” Anderegg says. “Second, we can start to plan for increasing risk and manage forests to reduce risk, like fires.”

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JOURNAL

Science

DOI

10.1126/science.abp9723 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A climate risk analysis of Earth’s forests in the 21st century

ARTICLE PUBLICATION DATE

2-Sep-2022