The report, “Endocrine Disrupting Chemicals: Threats to Human Health” provides a comprehensive update on the state of the science around EDCs, with increasing evidence that this large group of toxic substances may be implicated in rising global health concerns.

The report from the Endocrine Society, co-produced with the International Pollutants Elimination Network (IPEN), includes detailed analyses on exposure to EDCs from four sources: plastics, pesticides, consumer products (including children’s products), and per-and polyfluoroalkyl substances (PFAS), a class of thousands of chemicals known or suspected to be EDCs.

The Endocrine Society-IPEN report is being released during the U.N. Environment Assembly (UNEA-6) meeting in Nairobi. At UNEA key agenda items include welcoming the newly adopted Global Framework on Chemicals, advancing global action on highly hazardous pesticides, and threats to the circular economy from plastics and toxic chemicals. The groups’ report anticipates an update from UNEP and the WHO expected later this year on their 2012 Report on State of the Science of Endocrine Disrupting Chemicals.

“A well-established body of scientific research indicates that endocrine-disrupting chemicals that are part of our daily lives are making us more susceptible to reproductive disorders, cancer, diabetes, obesity, heart disease, and other serious health conditions,” said the report’s lead author, Andrea C. Gore, PhD, of the University of Texas at Austin. Gore is also a member of the Endocrine Society’s Board of Directors. “These chemicals pose particularly serious risks to pregnant women and children. Now is the time for the UN Environment Assembly and other global policymakers to take action to address this threat to public health.”

Hormones are natural chemicals that contribute to normal development, adaptation, and maintenance of bodily processes and health. By interfering with hormones and their actions, EDC exposure can impact many health-related functions, with consequences for increased risks of many serious conditions. Evidence suggests that EDCs in the environment contribute to disorders such as diabetes, neurological disorders, reproductive disorders, inflammation, and compromised immune functioning.

Two of the four analyses in the report look at EDCs used in plastics and as pesticides. Global production of plastics and pesticides is increasing even as scientists warn that chemical and plastic pollution is an escalating crisis. Glyphosate is the world’s most widely used herbicide, and a recent study found that glyphosate has eight of ten key characteristics of an EDC. Other studies have found links between glyphosate and adverse reproductive health outcomes. Plastics are made with thousands of known toxic substances, some of which are known or suspected EDCs. The report examines bisphenols and phthalates, two toxic chemical groups found in many plastics. Exposures to EDCs from plastics occur at all phases of plastics production, use, disposal, and even from recycled plastics.

The Endocrine Society-IPEN report notes that, while evidence of health threats from EDCs is mounting, current regulations have not kept pace. “EDCs are different than other toxic chemicals, but most regulations fail to address these differences,” said IPEN Science Advisor Sara Brosché, Ph.D. “For example, we know that even very low doses of endocrine disrupting chemicals can cause health problems and there may be no safe dose for exposure to EDCs. However, regulations typically do not protect against low-dose effects. We need a global approach to controlling EDCs based on the latest science with a goal of protecting the human right to a healthy environment.”

At the UNEA-6 meeting, IPEN is also releasing a new report on “The Global Threat from Highly Hazardous Pesticides,” highlighting ongoing health and environmental risks from HHPs, especially in low- and middle-income countries. DDT, glyphosate, and chorpyrifos, three HHPs reviewed in the Endocrine Society report, are also highlighted in the new IPEN report as they continue to pose health threats especially in the Global South.

In addition to plastics and pesticides, the report looks at EDC exposures from arsenic and lead, and from widely used per- and polyfluoroalkyl substances (PFAS), humanmade “forever chemicals” used as oil and water repellents and coatings. Lead remains in use in paint in many countries, as documented in recent IPEN reports. Endocrine-related conditions from lead exposure may include delayed onset of puberty and early menopause. Arsenic is a common metal that has long been linked to cancer and other health conditions, and more recent evidence shows that arsenic can disrupt multiple endocrine systems. PFAS are used in hundreds of products including clothing and food packaging, but recent studies show that some PFAS can disrupt hormones such as estrogen and testosterone and impair thyroid hormone functions.

The record results from a collaboration between the company First Solar European Technology Center (formerly known as Evolar) and solar cell researchers at Uppsala University.

“The measurements that we have made ourselves for this solar cell and other solar cells produced recently are within the margin of error for the independent measurement. That measurement will also be used for an internal calibration of our own measurement methods,” says Marika Edoff, Professor of Solar Cell Technology at Uppsala University, who is responsible for the study.

The previous world record was 23.35 per cent (Solar Frontier, Japan), preceded by 22.9 per cent (ZSW, Germany). Uppsala University has held the record before, the first time being in the 1990s in the research collaboration Euro-CIS.

“At one time we also held the record for a series-connected prototype. Even though it’s quite a long time since we held the cell record, we’ve often been just behind the best results and of course there are many relevant aspects to consider, such as the potential for scaling up to a large-scale process, where we have always been at the forefront,” Edoff says.

Solar cells are increasing rapidly worldwide and solar power accounted for just over 6 per cent of electricity around the globe in 2022 according to the International Energy Agency (IEA). The best solar modules of crystalline silicon, which is the most widely used material in solar cells, currently convert more than 22 per cent of sunlight to electric power and modern solar cells are both low cost and stable in the long term.

One target in solar cell research is to attain more than 30 per cent efficiency with reasonable production costs. The focus is very often on tandem solar cells, as being more efficient, but so far they have been too costly for large-scale use.

The world record of 23.64 per cent has been measured by the independent institute Fraunhofer ISE in Germany. The scholarly paper presents a thorough material and electrical analysis of the solar cell as well as a comparison with previous records for the same type of solar cell from other research institutions.

A solar cell’s most important properties are the ability to absorb light and the ability to transport energy to an electrical load. For this to succeed, the material must be able to absorb an optimal portion of sunlight while avoiding wasting this energy by converting it into heat within the solar cell.

CIGS solar cells consist of a glass sheet made of normal window glass that has been coated with several different layers, each of which has a specific task. The material that absorbs the sunlight consists of copper, indium, gallium and selenide (hence the acronym CIGS), with additions of silver and sodium. This layer is placed in the actual solar cell, between a back contact of metallic molybdenum and a transparent front contact. To make the solar cell as efficient as possible in separating out electrons, the CIGS layer is treated with rubidium fluoride. The balance between the two alkali metals, sodium and rubidium, and the composition of the CIGS layer are key to the conversion efficiency, i.e. the share of the complete solar spectrum that is converted to electric power in the solar cell.

When measurement institutes conduct their tests, they measure the solar cell efficiency using filtered light that mimics the sun in both intensity and spectrum. During measurement, the solar cell is kept at a controlled temperature and the independent institutes regularly send calibration solar cells to one another. To be registered as a world record, an independent measurement is required, which in this case was carried out by the measurement institute Fraunhofer ISE.

“Our study demonstrates that CIGS thin-film technology is a competitive alternative as a stand-alone solar cell. The technology also has properties that can function in other contexts, such as the bottom cell of a tandem solar cell,” Edoff says.

Several advanced measurement methods have been used to further understand the correlation between the efficiency and the solar cell structure: material from the solar cell has been characterised by nano-XRF (X-ray fluorescence spectroscopy) at the MAX IV facility in Lund, where a careful compositional analysis has been made. Transmission electron microscopy (TEM) at high resolution has been used to study cross sections of the solar cell, both composition as a function of depth and how the crystal grains are built up, as well as the interfaces between the layers. Using photoluminescence, the spectrum of the light emitted by the solar cell after excitation by a laser has been studied as a means to understanding how well the solar cell takes care of electrons internally. A solar cell that shines brightly has a lower share of internal heat losses than a solar cell that shines faintly. Finally, electrical measurement methods have been used to analyse the doping of the CIGS material.

“The fact that we now hold the world record means a lot for both Uppsala University and First Solar European Technology Center. For the CIGS technology, which is known for high reliability, a world record also means that it may offer a viable alternative for new applications in e.g. tandem solar cells. This is important for our research colleagues around the world. We hope that the analyses of the material and electric properties will provide a basis for further improvements in performance,” Edoff concludes.

“It is well known that some white dwarfs — slowly cooling embers of stars like our Sun — are cannibalising pieces of their planetary systems. Now we have discovered that the star’s magnetic field plays a key role in this process, resulting in a scar on the white dwarf’s surface,” says Stefano Bagnulo, an astronomer at Armagh Observatory and Planetarium in Northern Ireland, UK, and lead author of the study.

The scar the team observed is a concentration of metals imprinted on the surface of the white dwarf WD 0816-310, the Earth-sized remnant of a star similar to, but somewhat larger than, our Sun. “We have demonstrated that these metals originate from a planetary fragment as large as or possibly larger than Vesta, which is about 500 kilometres across and the second-largest asteroid in the Solar System,” says Jay Farihi, a professor at University College London, UK, and co-author on the study.

The observations also provided clues to how the star got its metal scar. The team noticed that the strength of the metal detection changed as the star rotated, suggesting that the metals are concentrated on a specific area on the white dwarf’s surface, rather than smoothly spread across it. They also found that these changes were synchronised with changes in the white dwarf’s magnetic field, indicating that this metal scar is located on one of its magnetic poles. Put together, these clues indicate that the magnetic field funneled metals onto the star, creating the scar.*

“Surprisingly, the material was not evenly mixed over the surface of the star, as predicted by theory. Instead, this scar is a concentrated patch of planetary material, held in place by the same magnetic field that has guided the infalling fragments,” says co-author John Landstreet, a professor at Western University, Canada, who is also affiliated with the Armagh Observatory and Planetarium. “Nothing like this has been seen before.”

To reach these conclusions, the team used a ‘Swiss-army knife’ instrument on the VLT called FORS2, which allowed them to detect the metal scar and connect it to the star’s magnetic field. “ESO has the unique combination of capabilities needed to observe faint objects such as white dwarfs, and sensitively measure stellar magnetic fields,” says Bagnulo. In their study, the team also relied on archival data from the VLT’s X-shooter instrument to confirm their findings.

Harnessing the power of observations like these, astronomers can reveal the bulk composition of exoplanets, planets orbiting other stars outside the Solar System. This unique study also shows how planetary systems can remain dynamically active, even after ‘death’.

Notes

* Previously, astronomers have observed numerous white dwarfs polluted by metals that were scattered over the surface of the star. These are known to originate from disrupted planets or asteroids that veer too close to the star, following star-grazing orbits similar to those of comets in our Solar System. However, for WD 0816-310, the team is confident that vaporised material was ionised and guided onto the magnetic poles by the white dwarf’s magnetic field. The process shares similarities to how auroras form on Earth and on Jupiter.

Extreme rainfall is one of the most damaging natural disasters costing human lives and causing billions in damage. Their frequency has been increasing over the last years due to the warming climate. For several decades, scientists have been using computer models of the Earth’s climate to better understand the mechanisms behind these events and to predict future trends. In a new study, now published in the journal Science Advances, a team of researchers from the Institute of Science and Technology Austria (ISTA) and the Max-Planck-Institute for Meteorology (MPI-M) led by ISTA postdoc Jiawei Bao used a new state-of-the-art climate model to study how cloud and storm clustering impacts extreme rainfall events — specifically in the tropics — in more detail than has been possible before.

“This new type of model with a much finer resolution showed that, with a warmer climate, extreme rainfall events in the tropics increase in severity more than was expected from theory due to clouds being more clustered,” Bao, who originally started this project during his previous postdoc position at the MPI-M, explains. “We can see that when clouds are more clustered, it rains for a longer time, so the total amount of rainfall increases. We also found that more extreme rain over high-precipitation areas happens at the cost of expansion of dry areas — a further shift to extreme weather patterns. This is due to how clouds and storms cluster together, which we could now simulate with this new climate model.” This new model, first proposed in 2019, simulates the climate with a much higher resolution than previous ones. Previous models could not factor in clouds and storms in as much detail, therefore missing much of the complex dynamics of air movement that create clouds and make them congregate to form more intense storms.

While the model simulates the whole world at once, the scientists focused their analysis on the area of the tropics around the equator. They did this because cloud and storm formation there works differently than in other latitudes. Caroline Muller, Assistant Professor at ISTA, adds, “Previous models have hinted at the influence of clouds clustering on precipitation extremes but could not provide the necessary data. In collaboration with our colleagues Bjorn Stevens and Lukas Kluft from the Max Planck Institute for Meteorology, our findings add to the growing body of evidence showing that cloud formation on a smaller scale has a crucial impact on the outcomes of climate change.”

Collaborative Models

Researchers all over the world are collaborating on creating more detailed and realistic models of the world’s climate to understand the effects of climate change. Climate models divide the Earth’s atmosphere into three-dimensional chunks, each with its own data about temperature, pressure, humidity, and many more physical properties. They then employ physical equations to simulate how these chunks interact and change over time to create a representation of the real world. As computing power and storage are not unlimited, these models have to introduce simplifications and scientist continuously work to making them more accurate.

Older generations of climate models use chunks of around 100 kilometers in horizontal length, which still result in tens to hundreds of thousands of them covering the whole globe. Advances in algorithms and supercomputers enabled scientists to increase the resolution of the models more and more. “We used a climate model developed at MPI-M and analyzed the data hosted at the German Climate Computing Centre in Hamburg with a resolution of just five kilometers which was very computationally expensive,” Bao adds. “All climate research is an immense collaborative effort by hundreds of people who want to contribute to our understanding of the world and our impact on it.”

Bao, who first got interested in climate research during his PhD at the University of New South Wales, Australia, and who now works as an IST-BRIDGE postdoctoral fellow at ISTA, wants to continue his work on extreme precipitation events to find more evidence for their causes and impacts using additional models.

Caroline Muller, who first studied mathematics and then found her passion for research questions with more real-world impact, and her research group use climate models to study air convection and the formation of clouds and storms at different scales — up to tropical cyclones — to better understand their causes and the impacts of climate change on society and nature.