Mangrove forests around the world provide a largely overlooked nitrogen-pollution cleanup service — one that, if humans had to pay for it, would cost $8.7 billion per year, a new study estimates.

Mangroves are salt-tolerant plants that grow between the high-tide and low-tide marks in tropical and subtropical coastal regions. Their tall, tangled roots trap sediments rich in microbes that break down nitrogen in the water into nitrogen gas (N₂) and nitrous oxide (N₂O), effectively removing this nutrient from the ecosystem.

Researchers were aware that mangrove forests are valuable carbon sinks and provide a host of other ecosystem services, including coastal defense against storm surges and a buffer against erosion. But these forests' ability to remove nitrogen is poorly understood, despite the havoc that nitrogen pollution is known to wreak in aquatic ecosystems, the authors of the new study told Live Science.

"We're still really in the infancy of trying to understand what is driving this nitrogen removal," Benoit Thibodeau, an assistant professor in the Department of Earth and Environmental Science at The Chinese University of Hong Kong, said in a joint interview with his co-author Ziyan Wang, a doctoral student in environmental science at the same university. "You're taking reactive nitrogen … and you're removing it to the atmosphere as N₂, which is nonreactive and has a residence time of thousands of years."

Nitrogen pollution is caused by excess nutrient runoff into water systems due to human activities such as agriculture. Between 2002 and 2010, this runoff amounted to 35.9 million tons (32.6 million metric tons) of nitrogen per year in freshwater ecosystems. This pollution promotes algal growth, leading to blooms that massively reduce oxygen availability for other species and release toxins into the water that can make animals and people sick.

Mangroves forests cover less than 0.1% of Earth's land surface, but they remove about 960,000 tons (870,000 metric tons) of nitrogen from water systems each year, the new study found. That's roughly equivalent to the mass of 650 giant sequoia (Sequoiadendron giganteum) trees — but optimal conditions for mangroves could boost their removal capacity to more than 5.5 million tons (5 million metric tons) per year, which is equivalent to the weight of over 4,000 giant sequoias. The findings were published April 29 in the journal Earth's Future.

Thibodeau and Wang analyzed the results of 51 previous studies, as well as measurements they took themselves, to estimate global nitrogen-removal rates in mangrove forests. They divided the data into actual removal rates, which are those observed in nature, and potential removal rates, which capture the amount of nitrogen that mangrove forests could soak up if temperature, salinity and nitrogen levels were optimal.

Then, the researchers calculated averages for the actual and potential rates — and these, together with a global mangrove area estimate of 52,459 square miles (135,869 square kilometers), yielded an actual removal rate of 960,000 tons per year and a potential removal rate of over 5.5 million tons per year.

Microbes in mangrove forests remove nitrogen via two main pathways: denitrification and anaerobic ammonium oxidation (anammox). Denitrification transforms nitrate in the water into nitrogen gas and nitrous oxide, which is a greenhouse gas. Anammox, on the other hand, converts nitrite and ammonium into nitrogen gas, which makes up 78% of the atmosphere and is not a greenhouse gas. These pathways work best with relatively high nitrogen concentrations, but there is a threshold past which removal slows, according to the study.

These pathways also occur in seagrass meadows and other coastal environments, but mangrove forests are especially good at removing nitrogen because their sediments are oxygen-poor, which promotes the right kind of microbial activity, Wang said.

Similar to carbon credits that people can purchase to offset their emissions from activities like flying, the researchers used a market-based credit approach to calculate the economic value of nitrogen removal in mangrove forests. Based on what municipalities in countries like Australia and the U.S. pay to get rid of nitrogen in their water systems, Thibodeau and Wang settled on a price of just over $10,000 for every metric ton of nitrogen removed anywhere in the world.

"Carbon has a very mature credit market now, but for nitrogen, it's not that mature," Wang said. "We did a very early investigation about how different markets, or different industries, deal with this kind of nitrogen pollution."

At the current rate of nitrogen removal, mangroves' cleanup service is worth $8.7 billion per year globally. If removal rose to 5.5 million tons per year, it would be worth around $57 billion annually, according to the study.

The researchers also calculated the economic value of carbon sequestration in mangrove forests and found it was 12 times smaller than that of nitrogen removal. Notably, carbon sequestration is also less stable than nitrogen removal is, because mangroves store carbon in sediments that can be disturbed. On the flip side, mangrove forests convert nitrogen in the water mostly into nitrogen gas, which stays in the atmosphere, Thibodeau said. Nevertheless, mangrove forests "have a very high rate of storage of carbon compared to other ecosystems," he added.

Mangroves are mostly threatened by sea-level rise and land clearance for infrastructure, Thibodeau said. The results highlight that "we're not only losing space or nature, but we're also losing a very important financial value."

Mangroves have a relatively high heat tolerance, but rising global temperatures could alter how the microbes they host consume nitrogen, Wang said. Specifically, these microbes may start to rely more on denitrification, which could release more of the greenhouse gas N₂O than at present.

China's Yangtze River is showing signs of recovery following the introduction of a 10-year ban on commercial fishing in 2021. The number of large fish has increased, and there has been recovery among endangered animals, including the Yangtze sturgeon (Sinosturia dabryanus) and the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis), new research finds.

"These results show that strong political decisions are required to restore biodiversity," Sébastien Brosse, an ecologist at the University of Toulouse in France and co-author of the new study, told Live Science via email. "This is an encouraging message because biodiversity loss is often seen as irreversible." The Yangtze is the longest and largest river in China. About 30% of the country's population lives within its drainage basin, and the 11 provinces and municipalities that make up the Yangtze River Economic Belt generate about 47% of China's total gross domestic product.

But rapid urban development since the 1950s, dam building, decades of overfishing, pollution and habitat degradation had all led to a decline in water quality and a biodiversity crisis. The Yangtze River dolphin (Lipotes vexillifer) and the Chinese paddlefish (Psephurus gladius) went extinct, and 135 fish species found in historical surveys disappeared.

This decline continued despite the establishment of a network of protected areas and an investment of more than $300 billion in water-quality management and improvement. In response, China took drastic measures: The country instituted a 10-year fishing ban across the entire Yangtze basin in 2021, used river police to enforce strict penalties, and continued broad environmental management.

To assess the effects of the fishing ban, Yushun Chen, a hydrobiologist at the Chinese Academy of Sciences in Wuhan, China, and his colleagues used data from between 2018 and 2023 to evaluate the health of fish communities in the Yangtze before and after the ban went into effect.

They found that overall, the total mass of fish collected in samples more than doubled between those dates, and there was a 13% boost in the number of species in the samples.

The overall number of fish stayed about the same, but larger-bodied species that are higher up in the food web, including the economically valuable black Amur bream (Megalobrama terminalis) and the white Amur bream (Parabramis pekinensis), grew, and they contributed a larger amount of the biomass. However, the total mass of smaller species sampled decreased by 18%.

The team's findings, published on Thursday (Feb. 12) in the journal Science, also included positive signs for migratory and endangered species. For example, populations of slender tongue sole (Cynoglossus gracilis) increased after the ban, and its freshwater migration extended farther upstream. Endangered fish species — such as the Yangtze sturgeon, Chinese sucker (Myxocyprinus asiaticus) and tube fish (Ochetobius elongatus) — also showed signs of recovery.

Another notable positive was the boost in numbers of the only freshwater mammal remaining in the Yangtze River, the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis), whose population rose by a third from 445 in 2017 to 595 in 2022. This gain may have resulted from a greater availability of bigger fish to eat; fewer deaths related to vessel strikes or fishing bycatch; and a reduction in other stressors, such as underwater noise from vessel propellers, the researchers suggested.

"In an era of unprecedented biodiversity losses and declines, especially in freshwater systems, this study offers a glimpse of hope regarding the future of biodiversity," said Lise Comte, a conservation ecologist at California-based Conservation Science Partners who wasn't involved in the research.

"It demonstrates that bold protection and restoration strategies can be efficient in slowing down and even reverting human impacts on ecological communities," she told Live Science via email.

Chen and his colleagues are still monitoring Yangtze River biodiversity, and they said the recovery is continuing. But they warned that the progress could easily be reversed if commercial fishing were to restart and that lasting biodiversity recovery will depend on sustained management that addresses all human pressures on river systems.

They also suggested that similar conservation measures might be useful on rivers such as the Mekong and the Amazon.

However, the Yangtze fishing ban had huge human and financial costs, as it involved the recall of 111,000 fishing boats, the resettlement of 231,000 fishers, and an investment of more than $2.74 billion in the Yangtze River Economic Belt.

"The promising findings demonstrate the resilience of these systems but are also a case study of an approach that I hope we don't have to emulate elsewhere," co-author Steven Cooke, a professor of biology at Carleton University in Ottawa, Canada, told Live Science via email. "Closing all fisheries in a river basin has significant socio-economic consequences. Fishers, and those in related industries, often move on, forever changing those communities. Managing fisheries in ways that do not require such a 'nuclear' option is always preferred."

A better approach would involve the ongoing assessment of fish populations; science-based fisheries management; and the study of watersheds as integrated systems that connect people, water and fish, he added.

Humans have found lead useful for thousands of years, but the metal's toxic effects didn't become well known until the 20th century. Now, using historical hair samples, researchers have shown that regulations targeting heavy-metal pollution were extremely effective at reducing the public's exposure to lead once its dangers were known.

"We have hair samples spanning about 100 years," study co-author Ken Smith, a demographer at the University of Utah, said in a statement. The study focused on people living in Utah.

"Back when the regulations were absent," Smith said, "the lead levels were about 100 times higher than they are after the regulations."

In the new study, published Monday (Feb. 2) in the journal PNAS, the researchers detailed their analysis of hair samples from 47 people who lived in the Greater Salt Lake City region as children and as adults. The study participants provided locks of their baby hair that had been preserved in family scrapbooks, as well as a current hair sample. The researchers analyzed the hair for lead using mass spectrometry, a technique that identifies chemical compounds in a sample.

Lead exposure is detrimental to human health, causing damage to the nervous system that can lead to developmental delays, seizures and learning problems, while also raising the risk of fertility issues and high blood pressure. There is no known safe level of lead exposure, the researchers wrote in the study.

A major source of toxic lead exposure in the first half of the 20th century was leaded gasoline. In the 1920s, tetraethyl lead — a compound containing carbon and lead — was added to gasoline to reduce engine "knocking," the pinging sound caused by the premature ignition of fuel. Although the U.S. Public Health Service realized as early as 1925 that leaded gasoline was causing health issues, the fuel additive was not fully banned in the U.S. until 1996.

However, key regulations on lead were established before the 1990s. The U.S. Environmental Protection Agency (EPA), which was created by then-President Richard Nixon in 1970 to address multiple air and pollution problems, resulted in an immediate decline in lead exposure, the researchers found in the new study.

Concentrations of lead in human hair from the Salt Lake City region were extremely high from 1916 to 1969, in part due to a lack of EPA regulation and in part because of two active lead smelter sites in the area. But from the 1970s to the 1990s, after the EPA was established and the smelting plants were shuttered, the average values declined by two orders of magnitude.

"Current concentrations of lead in hair from this population average almost 100 times lower than before the establishment of the Environmental Protection Agency," the researchers wrote.

One caveat is that the values of lead in hair do not correspond exactly to levels in the blood, which is physicians' typical standard for identifying people who need treatment for lead toxicity.

A hair sample "doesn't really record that internal blood concentration that your brain is seeing, but it tells you about that overall environmental exposure," study co-author Thure Cerling, a geologist at the University of Utah, said in the statement. So overall, the study showed that people were taking in a significantly larger amount of lead prior to 1970.

"It's just coming out of the tailpipe, goes up in the air and then it comes down," Cerling said. Lead lingers in the air for days and "it absorbs into your hair, you breathe it, and it goes into your lungs."

The researchers noted that, although their study demonstrates the effectiveness of environmental regulations in controlling toxic pollutants, such as lead, these regulations are now in danger of being rolled back.

Specifically, the researchers pointed to a March 12, 2025, announcement by the EPA and President Donald Trump that would deregulate many of the EPA's provisions that currently ensure U.S. residents have clean air, land and water. Although lead pollution is not specifically mentioned, experts have suggested that the announcement is a "roadmap" for rolling back regulations on air pollution in the manufacturing sector and wastewater from coal plants, among other things. At least one federal lawsuit has already been filed to overturn "presidential exemptions" to the EPA's Clean Air Act.

"We should not forget the lessons of history," Cerling said. "Those regulations have been very important," as evidenced by the EPA having "really, really positive effects" quite soon after it was established.

The historic hair study shows that the lax environmental standards of previous decades resulted in unhealthy lead levels but that these levels can be reined in with "science-based regulations," the researchers wrote.

Periodic table of elements quiz: How many elements can you name in 10 minutes?

A toxic chemical that pollutes groundwater originates high in Earth's atmosphere, a scientific flight has revealed.

Perchlorates, a group of chlorine-containing chemicals that can disrupt thyroid function, form on particles of smoke and organic material in the stratosphere, between 6 and 31 miles (10 to 50 kilometers) above the planet's surface, according to a new study.

Scientists already knew that perchlorates form high in the atmosphere, because the natural forms of these chemicals show signs of being zinged by cosmic rays from space. However, it wasn't clear exactly how and where they form.

The stratosphere is largely populated by tiny sulfuric acid particles, but the researchers found that perchlorates didn't stick to these common particles. Instead, the team found the toxic chemicals almost exclusively on particles rich in nitrogen and particles from smoke — neither of which frequently make their way so high into the atmosphere.

The question now is whether increasing human pollution of the stratosphere might also increase perchlorates contaminating groundwater, when they eventually fall to Earth's surface.

"We don't know if changing the particles in the stratosphere will cause more perchlorate or not," said Daniel Murphy, the program lead in aerosol properties and processes at the National Oceanic and Atmospheric Administration (NOAA) Chemical Sciences Laboratory. The new study is a call for more research on that question, he told Live Science.

Related: Scientists say sprinkling diamond dust into the sky could offset almost all of climate change so far — but it'll cost $175 trillion

Synthetic perchlorates are found in explosives, batteries, airbags and rocket propellant. Manufacturing can sometimes lead to groundwater pollution, but most perchlorates are natural. The Environmental Protection Agency (EPA) is set to propose national perchlorate drinking water regulations by November.

Murphy and his colleagues discovered where perchlorates form during a larger project to explore the aerosol particles of the stratosphere. The data mostly came from NASA's WB-57 aircraft, which can fly up to 62,000 feet (19,000 meters). Commercial flights typically stay between 30,000 and 42,000 feet (9,100 to 12,800 m).

"These were the most detailed measurements of the perchlorate," Murphy said. "They had information we'd never had before on what the perchlorate was like for that natural source in the stratosphere."

The researchers, who published their research July 28 in the journal PNAS, compared the perchlorates they detected to previous measurements of perchlorates in rocket fuel and found they were not the same kind. In other words, the stratospheric concentration is not caused by rocket launches but by natural processes in this layer of the atmosphere.

It's currently unclear whether the fact the perchlorates cling only to organic and smoke particles is an intriguing quirk of the chemical or if it has broader implications, Murphy said. If the existence of these particles enables perchlorates to form, adding more of them to the stratosphere could create more of the toxic chemical. This could be a concern because perchlorates that fall to the surface can last a very long time — at least 10,000 years in arid environments, according to 2010 research.

"We know, for example, that wildfires are increasing globally and that might mean that this natural source of perchlorate might increase," Murphy said.

Some geoengineering schemes also propose injecting particles into the stratosphere to reflect sunlight, which could be risky if those particles trigger perchlorate formation.

However, researchers are already set-up to investigate these chemicals. Perchlorate has been found on Mars, which means planetary scientists are already studying it. "People may have built up some lab instrumentation for that reason and they can shift it over," Murphy said. Laboratory studies on perchlorate chemistry can determine whether human activity might inadvertently increase perchlorates at such dizzying heights, he added.

Scientists have developed a new method to break down harmful "forever chemicals" by exposing them to a sunlight-activated material.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are chemicals found in many household products, including cookware, cosmetics, dental floss and waterproof clothing. True to their nickname, the chemicals take thousands of years to break down, enabling them to accumulate in the environment and our bodies.

PFAS have been used since the 1940s. Initially, they were valued for their nonstick properties, but now they are linked to a number of health impacts, including increased risks of autoimmune disease, developmental disorders, reduced fertility and cancer in humans. This has led some PFAS to be banned. But with nearly 15,000 types having been produced, roughly 98% of the U.S. population has these chemicals in their blood.

Now, a team of researchers has found a way to break down the chemicals, reducing them to components that include fluoride, which is harmless at low doses. They published their findings July 25 in the journal Small.

"PFAS contamination continues to pose a global health risk, and this research represents a critical step toward safer communities and cleaner ecosystems," lead researcher Cameron Shearer, a materials scientist at the University of Adelaide in Australia, said in a statement.

Related: Scientists find a simple way to destroy 'forever chemicals' — by beheading them

PFAS owe their persistence to their strong chemical bonds; they consist of a head (often charged oxygen molecules) linked to a tail of carbon and fluorine atoms. For PFAS to degrade, this bond must be broken — but this process is very difficult to achieve using traditional methods.

"Many water contaminants are degraded by adding a reactive chemical that binds to the carbon," Shearer said. "However, in PFAS molecules, the carbon atoms are protected in such a way that makes this process nearly impossible."

In recent years, researchers have been developing methods to break down PFAS using materials called photocatalysts, which absorb incident light to speed up chemical reactions. The scientists behind the new study turned to a photocatalytic material called cadmium indium sulfide, known for its ability to release reactive oxygen species — or free radicals — after being exposed to visible light.

After mixing the material with one common PFAS called perfluorooctane sulfonate (PFOS), the researchers watched as the photocatalyst absorbed light to generate free radicals that attacked the fluorine atoms in the bond.

Under optimized conditions, this led to the "complete breakdown" of around 99% of the PFOS molecules. The byproducts were components which the scientists say can be isolated and used to make toothpaste and fertilizer additives.

"The materials we have developed through our research could be used as part of PFAS-treatment chains that first capture and concentrate PFAS in water, which can then be degraded through exposure to our light-activated materials," Shearer said. "We plan to build on this study through our ongoing work improving the stability of the materials before they can be applied to large scale systems."

Researchers have identified gut bacteria that can absorb toxic "forever chemicals" in lab mice, according to a new study, potentially offering up a way to control PFAS levels in humans.

PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are synthetic chemicals used in a variety of products, from non-stick cooking pans to cosmetics. These substances are often nicknamed "forever chemicals" because they have strong chemical bonds that don't easily break down in nature and, in some cases, stick around for thousands of years. As a result, these chemicals pose a major pollution concern, both in our environment and in our own bodies.

Our drinking water and agricultural systems are already contaminated with PFAS to some degree, and as some of these chemicals can be absorbed through the skin and into our blood, there's no keeping them out of our bodies. Scientists are still untangling the health implications of PFAS, but exposure has been linked to various potential harms, including an increased risk of some cancers and disruptions to our immune system.

However, our bodies may also have a way of protecting themselves from these chemicals. The new study, published Tuesday (July 1) in the journal Nature Microbiology, investigated how human gut bacteria interacted with PFAS and found that nine species could effectively fend off the chemicals, at least in lab mice. The bacteria absorbed a good chunk of common PFAS that the mice were exposed to, which was then excreted in the mice's feces.

While there's a lot more work to be done, these findings suggest that we may be able to employ some bacterial species to control forever chemicals.

"The reality is that PFAS are already in the environment and in our bodies, and we need to try and mitigate their impact on our health now," study co-author Indra Roux, a researcher in the Medical Research Council (MRC) Toxicology Unit at the University of Cambridge, said in a statement. "We haven’t found a way to destroy PFAS, but our findings open the possibility of developing ways to get them out of our bodies where they do the most harm."

Related: How worried should we be about PFAS, the 'forever chemicals'?

PFAS resist water, oil and heat, making them useful in many different products. Today, there are thousands of different chemicals under the PFAS umbrella. While they are being phased out of some industries, like food packaging, many already exist in the environment and aren't going anywhere anytime soon.

To explore how gut bacteria interact with PFAS, the researchers first identified nine bacterial species that could absorb these chemicals and then gave those species to lab mice. The mice were then exposed to PFAS, including the common perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA). The bacteria absorbed between 25% and 74% of PFNA and 23% to 58% of PFOA, according to the study.

Accumulated PFAS didn't seem to affect the bacteria much. The PFAS aggregated (grouped together) in dense clusters within the bacteria, which appeared to minimize their impact on vital cell processes, according to the study.

"We found that certain species of human gut bacteria have a remarkably high capacity to soak up PFAS from their environment at a range of concentrations, and store these in clumps inside their cells," senior study author Kiran Patil, an investigator within the University of Cambridge’s MRC Toxicology Unit, said in the statement. "Due to aggregation of PFAS in these clumps, the bacteria themselves seem protected from the toxic effects."

The researchers noted in the study that their experiments involved giving mice a one-time dosage of PFAS, while humans — and other animals — typically experience low but chronic exposure to the chemicals.

Lawrence Wackett, a professor of biochemistry at the University of Minnesota Twin Cities who wasn't involved in the study, told Live Science in an email that the research was "particularly interesting" in light of another study published June 13 in the journal PNAS, which found that human gut microbial enzymes can break down carbon–fluorine bonds — the strong bonds present in PFAS.

"Taken together, there might be both sequestration and degradation of certain fluorinated compounds in the human gut," Wackett said.

In 2024, several farmers across Saskatchewan, Canada, had to deal with a bizarre situation: chunks of SpaceX space junk had crashed onto their land. As I helped a couple of these farmers negotiate the wild world of international space law, not significantly updated since the Apollo era, I knew this situation would become increasingly common.

The first generation of megaconstellation satellites, led by the SpaceX Starlink initial launch of 60 satellites in 2019, have now reached the end of their incredibly short operating lifetimes.

The end-of-life plan for virtually every satellite in Low Earth Orbit (LEO) is to burn them up in Earth's atmosphere. Economically, this makes sense: it takes a lot less propellant to bring a satellite down into a lower orbit than up into a higher orbit, sometimes called a "graveyard" orbit.

But the economic argument for bringing these satellites back down to Earth ignores the very real environmental consequences of atmospheric disposal. The chassis, leftover propellant, electronics, antennas, and solar panels don't disappear when a satellite "burns up" — the mass of the metals and plastics that comprise the satellite is deposited in the atmosphere as metal vapor.

When just a few satellites are burned every year, it's not a significant change to atmospheric chemistry. But Starlink alone plans to have 42,000 satellites with 5-year operating lifetimes, so the mass of metal vapor entering the atmosphere (particularly highly reactive aluminum and lithium) will exceed natural infall rates by 25 times or more.

This much extra metal vapor in the stratosphere can change atmospheric chemistry and may cause ozone depletion. By 2023, 10% of stratospheric aerosols already included metals from rocket and satellite reentries.

LEO satellites burning up are a source of upper atmospheric pollution that's going to increase exponentially — and scientists are only just beginning to study what this massive increase in metal vapor could do in the stratosphere.

Whatever parts of the reentering satellites don’t burn up will hit the ground. Just in the past few months, spacecraft pieces have fallen on Poland, Kenya, North Carolina, and Algeria, while scientists carefully tracked a 1970s Soviet Venus probe's reentry and speculated about ground casualty risks. That spacecraft, Kosmos 482, crashed into the Indian Ocean earlier this month.

While identifiable debris from only one Starlink satellite has so far been recovered, there are likely many, many more pieces already on the ground in other places that are covered by woods or mountains.

Related: 'No radio astronomy from the ground would be possible anymore': Satellite mega-swarms are blinding us to the cosmos — and a critical 'inflection point' is approaching

At some point, a bit of falling space junk will kill someone. Scientists recently calculated the risk of a casualty from one of the over 2,000 rocket bodies in orbit is 10% in the next decade, but that doesn’t include the tens of thousands of satellites expected to reenter in that same time period.

So what's the solution?

Leaving unmaneuverable, dead satellites in orbit is not an option. They pose a safety risk to other satellites, potentially orbiting for decades at 16,000 mph (25,000 km/h).

Collisions at these speeds are catastrophic, producing debris bullets that can crash into other satellites, producing more debris. The worst-case scenario is called Kessler Syndrome, where these collisions become self-propagating, and the debris field makes LEO unusable for decades to centuries.

Starlink has the highest density of operational satellites that has ever existed in orbit. It has reported an average of one collision avoidance maneuver within their megaconstellation every two minutes in the second half of 2024, and they have already launched hundreds more satellites into that orbital shell since then.

So far, Starlink has been impressively successful at avoiding collisions. But the frequency of collision avoidance maneuvers means that if there is a large solar flare, or their systems get hacked, or there's a simple human error, no maneuvers can be executed for any significant window of time — raising the risk of a collision.

Having fewer satellites in orbit naturally reduces the danger of collisions and the worst-case scenario of Kessler Syndrome. It also reduces light pollution from satellites, which is the reason I originally started worrying about megaconstellations. Satellites are already degrading astronomy research, including the discovery of potentially hazardous asteroids. Fewer satellites will allow astronomers to continue exploring space with telescopes, and stargazers to continue exploring space with their eyes.

LEO is a valuable resource that must be protected and shared in a way that benefits the most people while simultaneously protecting LEO for use by future generations. We cannot have tens of thousands of satellites in LEO without severe consequences for the atmosphere and an increasingly high likelihood of Kessler Syndrome, which will limit our use of satellites for decades to centuries.

This is the urgent challenge that satellite engineers and operators must now meet: if they need to provide services from orbit with fewer, longer-lived satellites, how will they do that? Without far-reaching, international regulation, or self-imposed limits from satellite companies, current practices in LEO threaten the planet, and our ability to explore beyond it.

Opinion on Live Science gives you insight on the most important issues in science that affect you and the world around you today, written by experts and leading scientists in their field.

Microplastic pollution from industrial waste has been contaminating freshwater ecosystems for decades, with evidence pointing to this run-off starting in the 1950s to 1970s. Now, though, new evidence suggests the extent of that pollution might be even broader than once thought.

In a study published April 25 in the journal Science of The Total Environment, scientists examined the larvae of caddisflies, small insects that build protective casings around themselves using plant material, sand and small stones in their environment. These casings, gathered in the 1970s and 1980s, came from clear, spring-fed streams in the Netherlands that were considered pristine at the time.

However, the study revealed that the larvae were incorporating plastic particles into their protective casings as early as 1971 — in other words, microplastics had infiltrated even these seemingly untouched ecosystems.

"The inclusion of plastic in the casing of a caddisfly means plastic is entering the food chain," said lead study author Auke-Florian Hiemstra, a doctoral candidate in evolutionary ecology at the Naturalis Biodiversity Center.

"Many birds and fish eat these caddisfly larvae, and some swallow them including their casing," Hiemstra told Live Science in an email. "If caddisflies have been affected by microplastics for over half a century, that means the broader ecosystem is affected too."

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The casing specimens in the study are part of the natural history collections at the Naturalis Biodiversity Center in the Netherlands. The researchers used a technique called energy dispersive X-ray analysis to reveal chemical elements and additives commonly associated with plastics inside the casings.

This provided a rare snapshot into the impact of microplastics on freshwater systems, which represent less than 4% of current studies on microplastics, Hiemstra said. Generally, the presence of microplastics in the 2000s is well documented, but the historical timeline of microplastic pollution has remained vague. This lack of historical data has made it difficult to assess how long ecosystems and human populations have been exposed to microplastics, thus complicating risk assessments and epidemiological studies.

So, how might this study change our understanding of the history of microplastic exposure and its potential impacts on human health?

Microplastics in nature and the body

Microplastics are tiny fragments of synthetic polymers that can take anywhere from hundreds to thousands of years to degrade. They're defined as being between 1 micrometer and 5 millimeters long. Today, they seem to be found virtually everywhere: in clouds, the air we breathe, food, drinking water, and human blood and breast milk. These particles stem from the breakdown of larger plastics, and in some cases, they are intentionally manufactured for use in certain cosmetics and cleaning products.

Research suggests that the human body clears out some larger microplastics measuring up to 150 micrometers long, while fragments smaller than 10 micrometers may be absorbed into tissues. But recent research suggests that some plastics in our bodies are even tinier than that.

While what qualifies as "nanoplastic" is still under debate, these ultrasmall particles are typically considered to be any plastic fragments smaller than 1 micrometer (or 1,000 nanometers) in diameter. A human hair, by comparison, is around 80,000 nanometers wide. Nanoplastics are small enough to potentially pass through cell membranes, studies suggest.

Matthew Campen, a toxicologist at the University of New Mexico, recently led a study that pointed to the presence of nanoplastics in human tissues. Using advanced, high-resolution imaging techniques, his team identified plastic fragments measuring no more than 200 nanometers in length — thin enough that they were translucent — in brain tissue from a few dozen organ donors.

After its publication, some of the analytical techniques used in the study were criticized, so the exact quantities of different types of plastic may be off, experts told Live Science. But by detecting nanoplastics, the findings expand upon previous work that relied on microscopes that could only detect particles up to 25 times larger.

That study, which included samples collected between 2016 and 2024, also suggested that later samples carried higher concentrations of plastics, and that the brains of individuals who died with dementia contained more plastic than healthy brains. These results raised questions about whether the public's plastic exposure has been increasing over time.

Hiemstra's new findings feed into that broader discussion and may have implications for how we understand the health risks of microplastics. If the pollutants have been present throughout the environment — not only near industrial sites — since the 1970s, that might reframe our understanding of where people have been exposed and for how long. Plastics not only accumulate in the environment, but also in the body, so better understanding the timeline and extent of exposure can help scientists unpack its long-term health outcomes.

As Hiemstra's study was focused on only the Netherlands, though, other work will need to be done to understand the history of microplastic pollution on a global scale.

Related: 'Very concerning': Microplastics can accumulate in cancer cells and may help them spread, study hints

What do microplastics do to our bodies?

Scientists are still working to understand exactly how microplastics and the chemicals within plastics — such as phthalates and per- and polyfluoroalkyl substances (PFAS) — might affect our bodies, Tracey Woodruff, a professor at the University of California, San Francisco (UCSF) who studies how pollutants affect reproductive and developmental health, told Live Science.

Early research has linked plastic exposure to the risk of various health conditions, including heart disease, lung disorders, cancer and Alzheimer's disease. In each of these cases, the link is correlative, so it's not clear if or how the plastics might be contributing to the diseases. In addition, in lab-dish studies, some types of plastics appear to be relatively harmless, while others have been shown to kill human cells in vitro.

In 2024, Woodruff and her team at UCSF's Program on Reproductive Health and the Environment published a systematic review of nearly 2,000 studies on the health effects of microplastics as part of a California state-commissioned report aimed at guiding policy decisions. The review identified potential health effects on respiratory, digestive and reproductive health, and particularly on sperm.

"While a link between chemicals in plastics and chronic diseases is clear, it's hard to separate the effects of the microplastic from its chemical additives," Woodruff noted.

She added that, "with rising cancer rates among younger people and increasing exposure [to microplastics] from early life, the potential long-term health risks — especially for those exposed in utero — remain a major concern," Woodruff said. Exposure to pollution is one of several competing theories for why the rates of certain cancers are rising in people under 50.

"More data will help address the uncertainty in the findings, but we're being exposed to [microplastics] right now, so it would be prudent to reduce exposures," Woodruff said.

While it's suspected that microplastics have negative impacts on human health, the World Health Organization emphasizes that the evidence for these effects is still limited and inconclusive.

"Our understanding of the potential harms of microplastic exposure is very preliminary at this stage," said Bernardo Lemos, a professor of pharmacology and toxicology at the University of Arizona and an adjunct professor of environmental epigenetics at the Harvard T.H. Chan School of Public Health. Lemos has led research to document the effects of microplastic exposure in humans and in model organisms, such as fruit flies, mice and fish.

"I am sure there will be many more studies documenting an abundance of microplastics in historical samples," Lemos told Live Science in an email. "It will be interesting to document how microplastics' abundance and quality change over decades." The Organisation for Economic Co-operation and Development, an intergovernmental organization, predicts that plastic production may triple by 2060.

Related: Humans inhale a staggering amount of microplastic every week. Here's where it ends up

Is it possible to avoid microplastics?

While Woodruff noted it would be prudent to reduce microplastic exposure, it's unclear what levels of micro- and nanoplastics we're realistically taking in on a daily basis. "Plastics can degrade into smaller fragments, but they persist, so we're going to be exposed to them for a very long time," Woodruff said.

She suggested that, at the individual level, people can reduce their exposure to microplastics and the chemicals in them by consuming fewer ultraprocessed foods, which are more likely to come into contact with plastic than whole or less-processed foods. She also suggested that it may help to avoid plastic containers, bottles and packaging where possible.

"There is still so little known about the history of microplastics," Hiemstra said. But thanks to collections that include specimens like the caddisfly casings, we may have unknowingly collected more evidence than we thought about the early days of this pollutant.

Other natural history collections around the world may harbor even older casings with microplastics, he suggested, highlighting the untapped value of such collections as tools for environmental science. They may offer a way to establish historical baselines of microplastic pollution, which are still largely missing from the record and could help us trace the true health impact of plastics.

This article is for informational purposes only and is not meant to offer medical advice.

Exposure to higher-than-average levels of outdoor air pollution and extreme temperatures raises the risk of a prolonged pregnancy, new research suggests.

An analysis of almost 400,000 live births in Australia has revealed that people who were exposed to very hot or cold temperatures, as well as to elevated levels of fine particulate air pollution (PM2.5), during pregnancy were more likely to give birth after 41 weeks compared with people who were not exposed to those conditions.

The average pregnancy normally lasts approximately 40 weeks, while babies who are born after 41 or 42 weeks are referred to as "late-term" or "post-term" births, respectively. Birth delays can increase the risk of birth complications associated with babies being excessively large — including vaginal bleeding or hemorrhage during delivery — as well as the likelihood of stillbirth or death after birth.

The scientists who conducted the new research described their findings in a paper published Jan. 31 in the journal Urban Climate. They claim to be the first to investigate how climate change may affect the risk of prolonged pregnancy.

Related: 'Dengue is coming': Climate-fueled rise in cases will affect the US, scientists warn

"We know that being 'born too soon' — preterm birth — has well-documented health risks, but little attention has been given to the risks associated with being 'born too late'," lead study author Sylvester Dodzi Nyadanu, a research associate in environmental health at Curtin University in Australia, said in a statement.

In the new study, the researchers examined how much PM2.5 air pollution 393,384 people were exposed to monthly shortly before and during pregnancy, from three months before conception to when they gave birth, based on where they lived. During the same time period, they also used a metric known as the Universal Thermal Climate Index (UTCI) to estimate how much thermal stress their bodies were under because of the weather, factoring in elements such as air temperature and humidity.

Overall, they found that 12% — or 47,380 — of the mothers had a prolonged pregnancy (meaning 41 weeks or more) and that higher levels of exposure to PM2.5 and thermal stress measured by the UTCI increased the odds of this happening. This was after they considered other factors that can influence pregnancy duration, such as smoking, socioeconomic status, race and ethnicity, and maternal age. People giving birth for the first time, people over 35, and people living in urban areas were particularly vulnerable to these effects.

Exposure to extreme temperatures and air pollution may prolong pregnancy in numerous ways, the researchers said. For example, both factors may increase the production of unstable molecules called "reactive oxygen species" which can disrupt hormonal function.

Such risks may become more apparent as climate change increases the number of extreme weather events and reduces air quality, Nyadanu said in the statement.

"This study highlights the need for targeted policies and preventative measures to reduce climate-related health risks, including better air quality regulations and public health initiatives aimed at protecting expectant mothers and children from extreme climatic conditions," he added.

This article is for informational purposes only and is not meant to offer medical advice.

This eerie satellite image shows a golden river of potentially toxic waste winding across the countryside after a deadly disaster at a diamond mine in South Africa.

On Sept. 11, 2022, a dam at a diamond mine in Jagersfontein suddenly collapsed, releasing a deluge of mining waste, known as tailings, which swept through the outskirts of the town and into the surrounding countryside, according to NASA's Earth Observatory.

The disaster killed at least three people and injured around 40 others, Bloomberg reported at the time. The flooding also destroyed dozens of houses, damaged cell phone towers, shut down roads, temporarily polluted drinking water and washed away hundreds of sheep, Reuters reported.

In the photo, you can see the collapsed section in the south wall of the dam. From there, the tailings flowed down the hillside in a massive, 1-mile-wide (1.6 kilometers) wave that eventually funneled into the nearby Wolwas Dam before spilling over into the adjoining Prosesspruit river.

Another aerial image of the site taken the day before the disaster (see below) helps show the scale of the torrent that was unleashed.

Related: See all the best images of Earth from space

In total, the dried tailings covered around 10 square miles (26 square kilometers) of farmland. Parts of the Prosesspruit also appear to have widened, suggesting that the torrent of mining waste may have eroded away the river's banks, according to the Earth Observatory.

It is unclear if any of the tailings remain in the area, but experts initially predicted that the dried waste would quickly crumble and either be blown away by wind or washed away by rain.

Toxic gold

Tailings are a muddy mix of dust, crushed rock, water and other byproducts left over from mining, according to Earthworks, a U.S.-based non-profit organization that supports communities impacted by mining and fossil fuel extraction.

The surplus slurry often contains trace quantities of metals, such as copper, mercury, cadmium and zinc, as well as other compounds, including petroleum, sulfuric acid and cyanide, according to Earthworks. This concoction makes the mixture appear gold when viewed from above, but also makes it potentially lethal to animals.

The diamond mine, once the deepest hand-excavated hole in the world, was also damaged from the flooding and has not reopened since the disaster. It is not clear if it ever will.

The mine produced two of the world's eight largest diamonds — the Excelsior Diamond and the Reitz Diamond, also known as the Golden Jubilee Diamond, according to the Cape Town Diamond Museum.

Every time generative artificial intelligence drafts an e-mail or conjures up an image, the planet pays for it. Making two images can consume as much energy as charging a smartphone; a single exchange with ChatGPT can heat up a server so much that it requires a bottle's worth of water to cool. At scale, these costs soar. By 2027, the global AI sector could annually consume as much electricity as the Netherlands, according to one recent estimate. And a new study in Nature Computational Science identifies another concern: AI's outsize contribution to the world's mounting heap of electronic waste. The study found that generative AI applications alone could add 1.2 million to five million metric tons of this hazardous trash to the planet by 2030, depending on how quickly the industry grows.

Such a contribution would add to the tens of millions of tons of electronic products the globe discards annually. Cell phones, microwave ovens, computers and other ubiquitous digital products often contain mercury, lead or other toxins. When improperly discarded, they can contaminate air, water and soil. The United Nations found that in 2022 about 78 percent of the world's e-waste wound up in landfills or at unofficial recycling sites, where laborers risk their health to scavenge rare metals.

The worldwide AI boom rapidly churns through physical data storage devices, plus the graphics processing units and other high-performance components needed to process thousands of simultaneous calculations. This hardware lasts anywhere from two to five years — but it's often replaced as soon as newer versions become available. Asaf Tzachor, a sustainability researcher at Israel's Reichman University, who co-authored the new study, says its findings emphasize the need to monitor and reduce this technology's environmental impacts.

To calculate just how much generative AI contributes to this problem, Tzachor and his colleagues examined the type and volume of hardware used to run large language models, the length of time that these components last and the growth rate of the generative AI sector. The researchers caution that their prediction is a gross estimate that could change based on a few additional factors. More people might adopt generative AI than the authors' models anticipate, for example. Hardware design innovations, meanwhile, could reduce e-waste in a given AI system — but other technological advances can make systems cheaper and more accessible to the public, increasing the number in use.

Related: New memory chip controlled by light and magnets could one day make AI computing less power-hungry

This study's biggest value comes from its attention to AI's broad environmental impacts, says Shaolei Ren, a researcher at the University of California, Riverside, who studies responsible AI and was not involved in the new research. "We might want these [generative AI] companies to slow down a bit," he says.

Few countries mandate the proper disposal of e-waste, and those that do often fail to enforce their existing laws on it. Twenty-five U.S. states have e-waste management policies, but there is no federal law that requires electronics recycling. In February Democratic Senator Ed Markey of Massachusetts introduced a bill that would require federal agencies to study and develop standards for AI's environmental impacts, including e-waste. But that bill, the Artificial Intelligence Environmental Impacts Act of 2024 (which has not passed the Senate), would not force AI developers to cooperate with its voluntary reporting system. Some companies, however, claim to be taking independent action. Microsoft and Google have pledged to reach net zero waste and net zero emissions respectively by 2030; this would likely involve reducing or recycling AI-related e-waste.

Companies that use AI have numerous options to limit e-waste. It's possible to squeeze more life out of servers, for instance, through regular maintenance and updates or by shifting worn-out devices to less-intensive applications. Refurbishing and reusing obsolete hardware components can also cut waste by 42 percent, Tzachor and his co-authors note in the new study. And more efficient chip and algorithm design could reduce generative AI's demand for hardware and electricity. Combining all these strategies would reduce e-waste by 86 percent, the study authors estimate.

There's another wrinkle as well: AI products tend to be trickier to recycle than standard electronics because the former often contain a lot of sensitive customer data, says Kees Baldé, an e-waste researcher at the United Nations Institute for Training and Research, who wasn't involved with the new study. But big tech companies can afford to both erase that data and properly dispose of their electronics, he points out. "Yes, it costs something," he says of broader e-waste recycling, "but the gains for society are much larger."

This article was first published at Scientific American. © ScientificAmerican.com. All rights reserved. Follow on TikTok and Instagram, X and Facebook.

In summer 2024, several news outlets chronicled the "nightmarish" impacts Texas communities endured due to the din of noise emanating from nearby cryptocurrency mines.

Residents of these communities reported that the unrelenting noise caused them to experience a range of ailments, including high blood pressure, chest pain and tinnitus. The noise levels of the cryptocurrency mines allegedly reached 72 decibels — well above the 55 dB limit beyond which the World Health Organization (WHO) deems to be increasingly dangerous for public health.

These recent reports have stoked ongoing discussions about the potential health hazards of cryptocurrency mining. In a thinkpiece published Sept. 26 in the journal JAMA, three scientists argue that we are experiencing a "digital oil boom" that could have serious health consequences for everyone — not only the communities that live near mines. This problem extends beyond noise pollution, encompassing health risks associated with increasing energy consumption and accelerated climate change.

Related: 'Any protein you can imagine, it can deliver': AI will help discover the next breakthrough in RNA, says Nobel Prize winner Dr. Drew Weissman

Energy-intensive mines

Cryptocurrency, a virtual currency that harnesses the blockchain, uses a network of computers to report transactions between users, which are documented in a digital ledger. The network is decentralized, meaning that it is not controlled or owned by any one person or group, unlike a traditional central bank, for instance. This structure allows users to transfer currency more quickly and cheaply and with less of a paper trail, compared with traditional banking.

Since its advent, cryptocurrency has experienced several bubbles and crashes — however, it still remains popular worldwide, and the cryptocurrency market has now become a multibillion-dollar industry.

The first and arguably most popular type of cryptocurrency is Bitcoin, which was invented in 2009. Bitcoin relies on something called a "proof-of-work" algorithm, a calculation that essentially verifies the accuracy of transactions added to the digital ledger. The process of completing these calculations is very energy-intensive, and it becomes exponentially more difficult over time.

Consequently, Bitcoin data centers, referred to as "mines," require more and more energy to function over time. In the U.S. alone, cryptocurrency mining is estimated to represent around 0.6% to 2.3% of all electricity consumption in the country.

The energy-hungry industry could raise communities' reliance on peaking power plants, meaning power plants that kick in only at times of peak demand, Mary Willis, co-author of the JAMA article and an assistant professor of epidemiology at Boston University, told Live Science.

The problem is that these plants run on fossil fuels. In terms of their direct impacts, these fumes contain air pollutants that can partly drive diseases, such as stroke, heart disease and lung cancer. Historically disadvantaged racial or ethnic communities are most likely to carry the burden of these health impacts, as plants are often built where those communities live.

Beyond harmful air pollutants, higher demands for fossil fuels also increases the release of greenhouse gases into the atmosphere, thus escalating climate change.

"Crypto mining uses mostly fossil fuel electricity, which comes from coal and natural gas power plants," Benjamin Jones, an associate professor of economics at the University of New Mexico who was not involved in the JAMA article, told Live Science in an email.

"These in-turn generate emissions of CO2 and other air pollutants, which contribute to climate change and harm human health," he said. Such harmful effects include spurring the spread of infectious diseases and the number of deaths tied to extreme weather events, such as heatwaves and major storms.

Blackouts and noise pollution

Another concern is that many cryptocurrency mines are in locations with fragile electrical grids, such as Texas, Willis said. A winter storm in February 2021 caused the states' power grid to fail and highlighted its precarity.

Crypto mines could put additional stress on the grid, exacerbating the risk of blackouts, Willis said. Power outages can have numerous health consequences, including raising the risk of carbon-monoxide poisoning from generators; gastrointestinal illnesses as refrigerators stop working; and deaths in hospitals due to medical equipment shutting down.

On top of these risks related to energy use, cryptocurrency mines can be really noisy. Many communities are extremely worried about this, Willis told Live Science. Exposure to high levels of noise is associated with sleep disturbances, increased blood pressure and heart disease, among other health issues. Excessive noise has also been tied to inflammation in the brain, which may have knock-on impacts in the circulatory system.

For now, many of these health effects are theoretical. Besides anecdotal reports out of places like Texas, there isn't much good data on the health impacts of these mines, Willis said. For starters, there's currently no systematic way to actually track where the mines are located, she said.

In February 2024, the U.S. Energy Information Administration launched a system to track energy consumption from cryptocurrency mines. At the time, the agency said it had identified 137 mines in 21 U.S. states, with Texas, Georgia and New York hosting the majority.

But a month later, this data collection was discontinued following a federal court case initiated by the crypto industry, the JAMA authors wrote. In this case, it was successfully argued that government monitoring would cause "irreparable injury" to the industry.

Without data on the locations and energy use of crypto mines, it will be impossible to fully understand the health implications of cryptocurrency mining, Willis and her co-authors argued.

The trio is now trying to figure out the best way to locate these mines. Only then, they say, might these predictions about the health impacts of the mines be confirmed.

This article is for informational purposes only and is not meant to offer medical advice.

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A giant cloud of haze frequently fills this ancient valley at the foot of the Himalayas, which was once an enormous freshwater lake. Although the stunning spectacle results from a natural phenomenon, this particular example was caused by human activity.

The Kashmir Valley is a large, bowl-like ravine that's around 84 miles (135 kilometers) long and 20 miles (32 km) wide. It is surrounded by mountains on all sides, including parts of the Himalayas to the north, south and west. The floor of the valley is around 6,000 feet (1,800 meters) above sea level, on average, but some of the surrounding peaks tower up to 4,000 feet (1,200 m) above the valley's base.

Until around 4.5 million years ago, the Kashmir Valley was a massive freshwater lake, according to NASA's Earth Observatory. Today, the only evidence of the lake is the bowl-like shape of the valley and the sandy, clay-like sediment across the valley's floor.

But under certain conditions, giant clouds of haze can form there, filling the space once occupied by water. This haze, which is normally made from mist and fog, forms when warm air passes over cool ground, known as a temperature inversion, which traps water vapor between the two. Once it has formed, the haze is contained within the valley by the tall surrounding peaks, sometimes for days on end.

Temperature inversions frequently occur in the winter, when the ground is cooler. They are more likely to happen when snow is on the ground, like the powder visible around the rim of the valley in this photo.

Related: See all the best images of Earth from space

However, in this case, only a small percentage of the haze was mist or fog. Instead, most of the cloud consisted of pollution from nearby infrastructure. Multiple satellites detected high levels of air pollution on the day this photo was taken, according to the Earth Observatory. Most of this pollution likely came from charcoal production factories and biomass-burning power plants, which provide the surrounding area with electricity.

Although the Kashmir Valley is no longer a lake, it is still home to several smaller lakes dotted around the floor of the rocky bowl. However, these lakes are also feeling the effects of human-related stressors.

Satellite imagery taken over the past few years shows that most of the valley's lakes are suffering from "eutrophication." During this process, an overabundance of nutrients enters the local waterways as a result of urbanization, triggering algal blooms and an explosion of plant life on the surfaces of these lakes that then starve the waters below of oxygen and make them toxic to most aquatic life.

The valley's largest body of water, Wular Lake, has suffered eutrophication across more than half of its waters at various points over the past decade, which has drastically reduced its biodiversity.

The extra nutrients are entering the lakes because the surrounding forests have been cleared for roads, houses and farmland.

Global warming is burying huge amounts of silver beneath the South China Sea — and the same could be happening across the world's oceans, scientists say.

The amount of silver trapped in marine sediments off the coast of Vietnam has increased sharply since 1850, the new study shows. This coincides with the start of the Industrial Revolution, when humans began pumping greenhouse gases into the atmosphere on a large scale.

This is the first time research has highlighted a possible link between silver cycles in the ocean and global warming, study lead author Liqiang Xu, an associate professor in the department of geosciences at the Hefei University of Technology in China, told Live Science in an email. The discovery indicates global warming could have unknown impacts on other trace elements, too, Xu said. (Trace elements are elements like cobalt, zinc and iron that are present in tiny amounts in the environment but may serve as essential micronutrients for life.)

Like other elements, silver originates on land and enters the oceans primarily through weathering, where rainwater leaches elements from rocks and carries them into rivers.

Certain regions of the ocean are enriched with silver due to heavy river inputs, atmospheric dust, human emissions and hydrothermal vents. Silver in its ionic form (Ag+) is toxic for marine creatures, Xu said, but very little is known about how it interacts with wider ocean ecosystems.

Related: Cutting pollution from the shipping industry accidentally increased global warming, study suggests

To find out more about how silver behaves in marine environments, Xu and his colleagues analyzed a sediment core from the Vietnam upwelling area in the eastern South China Sea. Upwelling areas are coastal regions where cold water rises from the seafloor, hauling up nutrients from the deep that sustain rich surface ecosystems.

The core was split into two zones, according to the study, published Aug. 13 in the journal Geophysical Research Letters. Silver concentrations decreased from the base of the core, dating to roughly 1200 B.C., up to about 3 inches (7 centimeters) from the top. But the upper end of the core showed a very different trend.

"Burial of [silver] over the past 3,200 years shows an abrupt increase around 1850," the researchers wrote in the study. The timing is "in concordance with the atmospheric CO2 record," they added, suggesting that climate change accelerates silver burial in some marine sediments.

Concentrations of silver in upwelling areas are generally high, especially in areas where humans add more silver to the mix via industry and pollution, according to the study. Such areas include coastal Massachusetts and the San Francisco Bay, which researchers previously dubbed the "silver estuary."

Silver levels off the coast of Vietnam were naturally high and similar to levels previously recorded in upwelling areas off Canada, Mexico, Peru and Chile, Xu said. "However, these studies did not link the high concentrations with global warming," he said.

Global warming boosts water temperatures and coastal winds, which combine to increase the intensity of upwelling. This leads to more nutrients rising to the surface, increasing the abundance of algae that feed the entire food chain. High levels of dissolved silver in these regions could mean organisms absorb more silver than elsewhere. When they eventually die and sink, this silver drops down to the seafloor.

"Silver enters the sediments together with organic matter," Xu said. "Many upwellings strengthened as a result of global warming, and we believe silver in sediments of all these areas is increasing."

The authors of a 2021 review of trace metals in the ocean agreed that dead organisms may be transporting silver to the seafloor, although several other factors could also be at play, they said. For example, low oxygen levels might be boosting silver entrapment in sediments through chemical reactions, four of the authors told Live Science in an email.

"There is strong evidence that low-oxygen regions in the ocean are expanding," they said. "If silver trapping is increasing in these low-oxygen areas, it could indeed be happening on a broader scale."

If this is happening on a global scale, it could be a problem because the silver could potentially escape and poison ocean ecosystems, Xu said. "High levels of silver in sediments have a potential to be released to seawater," he said.

If the silver doesn't escape back into the water, it will eventually find its way to land, the authors of the review said. "Nothing is truly lost, only relocated," they said.

On a warm spring day in 2019, researchers bored into the earth beneath Cairo's urban streets. Just over a kilometer away, the Great Pyramid of Giza shimmered on the horizon. Some 4,600 years earlier, as laborers constructed the Great Pyramid, the contemporary dig spot lay on the sandy floor of Khufu Harbor.

In this ancient harbor—the world's oldest known port—researchers said they've identified the first major instance of human-induced metal contamination. Though the Giza necropolis is famous for its pyramids and shriveled mummies, a new study published in Geology offers unprecedented evidence of a largely unheralded aspect of ancient Egyptian civilization: persistent, centuries-long metalworking.

The discovery sheds light on life beyond the pharaonic and princely elites of ancient Egypt, researchers said. "We'd like to know more about 95% of the people rather than the elite," said Alain Véron, a geochemist from France's Aix-Marseille Université. His sentiments echo the thoughts of Christophe Morhange, a geoarchaeologist from the same institution, who underscored the importance of the sedimentary record in reconstructing historical narratives.

Related: Long-lost branch of the Nile was 'indispensable for building the pyramids,' research shows

"The sediments are as important as monuments," Morhange said, highlighting the often-overlooked significance of the ground beneath our feet.

A surprising history of contamination

The researchers used geochemical tracers to investigate metalworking activities around ancient Khufu Harbor. Located along a now defunct branch of the Nile near the Giza Plateau, the harbor was essential for transporting materials and was the site of a major copper toolmaking industry. These tools, some of which workers alloyed with arsenic for added durability, included blades, chisels, and drills to work materials like limestone, wood, and textiles. Researchers used inductively coupled plasma–mass spectrometry (ICP-MS) to measure levels of copper and arsenic, as well as of aluminum, iron, and titanium, with six carbon-14 dates to establish a chronological framework.

The study traced the onset of metal contamination to around 3265 BCE, earlier than researchers anticipated. Contamination during this Predynastic period suggests that human occupation and metalworking at Giza began more than 200 years earlier than previously documented.

Although researchers have found direct evidence of Predynastic civilization in only 13 graves north of Giza, Morhange believes the geoarchaeological record yields more clues. With so much focus on the pyramids and other tombs, he explained, previous researchers might have overlooked evidence of the site's earlier occupation.

"You only find what you are looking for," he said.

Researchers found that metal contamination peaked during late pyramid construction around 2500 BCE and persisted until about 1000 BCE. "We found the oldest regional metal contamination ever recorded in the world," Véron said. Levels of copper during this period were "5 to 6 times higher than the natural background," he continued, indicating significant local industrial activity.

Andrew Shortland, an archaeological scientist from Cranfield University in the United Kingdom who was not involved in the study, expressed concerns about the proposed timeline. "I don't think six dates is enough," he said, referring to the number of carbon-14 dates used.

Nevertheless, Shortland acknowledged the study's broader conclusions about human-induced metal contamination at Giza.

Adapting to environmental hardship

The study provided further insight into how ancient Egyptians adapted to environmental challenges. As the Nile River receded and Khufu Harbor shrank, metalworking continued. As the Nile reached its lowest level, around 2200 BCE—a period marred by civil unrest and grim rumors of cannibalism—metal contamination remained high, suggesting a resilient infrastructure and workforce.

Véron explained that the receding Nile initially presented opportunities for local communities. Previous palynological research—the study of pollen grains—has shown that agricultural activity surged as the waning Nile exposed fertile floodplains. Even as pyramid construction at Giza ceased, metalworking likely persisted to support burgeoning pastoral activities.

Dominik Weiss, a geochemist from Imperial College London, found the study "extremely well done and carefully conducted." Noting the allure of high-visibility sites like the Giza necropolis, he celebrated the new link between geochemistry and history and the possibility of shedding light on the lives of everyday ancient Egyptians.

"The chemical imprint of human activity remains, and that cannot be erased," Véron said.

This article was originally published on Eos.org. Read the original article.

Certain bacteria can degrade the strong bonds that give "forever chemicals" their long shelf life, and this hints at potential low-cost treatments that could cleanse water of concerning PFAS.

PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are human-made compounds found in many products. They contain strong chemical bonds that do not easily break down, making them difficult to remove from our bodies and the environment.

PFAS have been linked to a variety of health effects, and this past April, the Environmental Protection Agency set limits on the concentrations of six common PFAS in drinking water. This move highlighted a need for effective ways to clean up polluted waters.

Now, in a study published July 17 in the journal Science Advances, researchers reported for the first time that four species of Acetobacterium can degrade the bonds in some PFAS. This includes unsaturated PFAS, whose chemical structure makes them easier to break down than so-called saturated PFAS. Examples of these chemicals include PFMeUPA and FTMeUPA, which are not yet regulated by the EPA.

Related: PFAS 'forever chemicals' to officially be removed from food packaging, FDA says

"PFAS degradation using microbes is one of the most sought-after technologies in wastewater treatment and waste management," Nirupam Aich, an associate professor of engineering at the University of Nebraska-Lincoln who was not involved in the research, told Live Science in an email.

There are already some effective approaches to treating PFAS, including filtration and heat treatment. However, using biological approaches involving bacteria could have unique advantages. According to the study authors, the approach could be low cost and easily injected into groundwater beneath the Earth's surface, where many existing treatments are challenging to apply. Groundwater supplies about one-third of U.S. drinking water.

The microbes highlighted in the new study break down carbon-fluorine bonds in some unsaturated PFAS. This process, known as defluorination, is driven by enzymes that split the chemical bonds, thus releasing fluoride atoms. These atoms would usually kill bacteria. But the researchers found that the Acetobacterium species have specialized channels that pump fluoride out of their cells and into the environment, enabling the bacteria to survive.

This may be part of a defense mechanism the bacteria evolved to detoxify compounds that would otherwise kill them, senior study author Yujie Men, an associate professor in the Department of Chemical and Environmental Engineering at the University of California (UC) Riverside, told Live Science in an email.

After pinpointing the defluorinating enzymes, the team scoured genomic databases to see if other Acetobacterium also had the same enzymes and pumps. They found defluorinating Acetobacterium in wastewater samples from North America, Europe and some parts of Africa and Asia. Additional clues hint that they may also be found in soil and groundwater, the study authors noted. Acetobacterium species are commonly found in wastewater, but little else is known about them and their defluorinating enzymes, Men said.

Related: Is drinking rainwater safe?

In previous work, Men and colleagues identified other bacteria that could break down the carbon-chlorine bonds found in some PFAS, triggering a reaction that dechlorinated and then destroyed the forever chemicals. The scientists' more recent finding adds to the number of known PFAS compounds that can be degraded by microbes.

This line of research could guide the search for more PFAS-degrading bacteria, leading to the discovery of new enzymes and the development of biotechnologies that accelerate these natural processes, Men said.

Microbial degradation of PFAS usually refers to using microbes in wastewater treatment to degrade PFAS prior to the water being disinfected and returned to the drinking water supply, Aich said. The major challenge of this approach has been the rarity of microbes that can break down the carbon-fluorine bonds. Even if microbes are able to degrade the chemicals, the rate of degradation can be slow.

This study is one of the first to provide insights into the specific mechanisms and bacterial enzymes that could be isolated and improved to increase those degradation rates, Aich said.

The researchers are now working on material-microbe interfaces that combine the defluorination ability of bacteria with materials that enhance the breakdown of PFAS. The properties of these materials change in response to electrical fields, and this enables them to destroy any byproducts leftover by the bacterial enzymes, said Chong Liu, an associate professor of chemistry and biochemistry at UCLA who led the research on interfaces. Thus, material-microbe interfaces provide a swift one-two punch to PFAS, Liu told Live Science in an email.

More research is needed to unpack the exact biochemistry of the defluorinating enzymes and their potential effect on larger scales, Men said.

"It is very unlikely that individual microbes could become a global solution to PFAS contamination," she noted. Nonetheless, their work points to avenues for using bacteria in biotechnologies that could work alone or in combination with other approaches.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

Editor's note: Since this story was published July 31, two Olympic triathletes have fallen ill following races in the Seine, although it's unclear if the illnesses were directly related to exposure to the river. Due to the sicknesses, Belgium’s triathlon mixed relay team withdrew from the Aug. 5 race and Switzerland's team changed its race lineup. 

Rain showered down on athletes, onlookers, can-can dancers and opera singers at the 2024 Paris Olympics opening ceremony on July 26, and more rain over the weekend reportedly drove an uptick in disease-causing bacteria in the Seine river.

This decline in water quality prompted officials to cancel the swimming portion of a training session for the triathlon events, and the men's race, scheduled for Tuesday (July 30), was postponed. Finally, on Wednesday (July 31), both the women's and men's triathlons were allowed to proceed, with athletes plunging headfirst into the Seine for a 0.9-mile (1.5 kilometers) swim before jumping onto bikes for the next leg of the race.

France and Great Britain snagged gold in the women's and men's races, respectively. But even as the athletes take the podium, there's more river swimming to come, as the mixed relay and marathon swimming events are scheduled for next week.

Are there any lingering concerns about the water quality in the Seine? And what risks could subpar water pose to the competitors? Live Science spoke with experts to find out.

Related: Will Olympic athletes ever stop breaking records?

Poop pollution

Paris invested the equivalent of $1.5 billion in making the Seine swimmable in time for the Olympics. The renovation involved connecting thousands of residences to municipal sewer systems and constructing a huge underground cistern. This massive tank, which holds 20 Olympic swimming pools' worth of water, is intended to prevent untreated sewage from flowing into the river.

Paris has a combined sewer network that captures stormwater and wastewater, funneling both to treatment plants. But in times of heavy rain, some untreated water is instead diverted into the Seine and its tributaries to prevent disastrous backups. The new basin beneath Paris helps curb such outflows by capturing excess water and then slowly releasing it back into the sewers so it can go through the normal treatment process.

This cistern was completed in May. But even so, when it rains in Paris, the quantity of bacteria-carrying poop in the Seine still spikes. In particular, rain comes with an uptick in Escherichia coli, a bacterium found in both human and animal feces.

"Elevated E. coli levels are to be expected following rain events," Sarah Lowry, a doctoral candidate in environmental engineering at Stanford University, told Live Science in an email. E. coli acts as a general indicator of fecal contamination, so its presence implies that other common poop-borne pathogens, such as norovirus and Salmonella, are likely also in the water. In addition to the germs from human wastewater, some of these pathogens come from animal feces that get washed into the river, Lowry noted.

After such an influx of poop, one can expect the related pathogens to then decline due to sun exposure and fluctuating temperatures in the water. In terms of how long that takes, "we are talking about days, not weeks in general," Patrick Gurian, a professor and the head of the Environmental Engineering Program at Drexel University, told Live Science in an email.

"In general, if levels of E. coli rise in a natural, moving body of water because of runoff from rain, those levels should start to drop when the rain stops," said Mia Mattioli, the team lead for the Environmental Microbiology and Engineering Laboratory within the Centers for Disease Control and Prevention's (CDC) Waterborne Disease Prevention Branch.

Related: What are the most polluted cities in the world?

"However, the time it takes for the levels to drop will depend on upstream runoff, surrounding land use, and drainage systems," Mattioli told Live Science in a written statement. Additional factors, such as the cloudiness of a given body of water, can also affect how quickly germs die off, Lowry added. "It's hard to say without knowing the specifics of a particular site," she said, but it typically takes one to two days.

Following the weekend's rain, another rainstorm hit Paris in the early morning hours Wednesday, The Washington Post reported. A few hours later, organizers met to discuss the results of the latest water-quality tests and deemed the water safe for racing. The rain let up around when the women's race started at 8 a.m.

"The results of the latest water analyses, received at 3:20 a.m., have been assessed as compliant by World Triathlon allowing for the triathlon competitions to take place," the organizers said in a statement sent to news outlets Wednesday. However, the Olympic organizers previously said the water samples used to make these decisions are taken 21.5 hours prior — which means they would have been taken before Wednesday's rainstorm. The test results from Wednesday have yet to be released.

What's the risk?

World Triathlon, the international governing body for triathlons, bases its water safety guidelines on the European Union's Bathing Waters Directive. These guidelines set a threshold for the E. coli level that's considered safe enough for swimming in inland waters: 900 colony-forming units per 100 milliliters (CFU/100mL).

That number came from epidemiological studies that looked at rates of illness among swimmers and then correlated them with the levels of an indicator bacterium, such as E. coli, in the body of water where they swam, Lowry explained. Such thresholds are specific to a given geography and type of water — salt versus fresh — so "there is no one number that is 'best' to set a threshold," she noted. That's why standards may vary among locations.

Paris Mayor Anne Hidalgo and Paris 2024 Chief Tony Estanguet took a dip in the Seine two weeks prior to the Games to demonstrate their confidence in its cleanliness. But notably, data later showed that E. coli levels were 985 CFU/100mL that day, The Associated Press reported. That's slightly above the "sufficient" threshold set forth in the guidelines.

So, what's the potential risk of swimming in poop-contaminated water?

In general, the various disease-causing germs found in feces can cause stomach cramps and diarrhea, which can lead to dehydration, Mattioli said. They can also cause ear, eye, respiratory and wound infections. "CDC cannot speak to the status of the Seine at present and defer to French authorities who are monitoring the water quality," she added.

E. coli, specifically, is not always a threat to human health — in this context, the microbe is being used as a benchmark to see if there's likely a concerning amount of poop in the water, Lowry emphasized. Most E. coli strains are harmless, but some can cause gastrointestinal problems and urinary tract infections. One type, called Shiga toxin-producing E. coli, can spark more-serious illnesses, involving bloody diarrhea and, in some cases, blood clots and kidney damage.

An individual's likelihood of getting sick after swimming in poop-contaminated waters varies depending on their existing immunity and their degree of exposure to the germs, Lowry said.

"The amount you ingest is usually the problem," Gurian said. Skin exposure can be an issue in some cases, but "by and large, the less you drink, the safer you are." In addition to avoiding swallowing the water, swimmers can protect themselves by wearing earplugs, nose plugs and goggles; covering any open wounds as much as possible with waterproof bandages and changing those bandages after swimming; and showering after swimming, Mattioli said.

Current weather forecasts suggest that more rain could befall Paris in the coming days, so the Seine's quality may continue to fluctuate. Only time will tell if the upcoming scheduled races will be postponed, downgraded to exclude swimming or moved to alternate arenas — or if anyone will wind up ill after braving the river's waters.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

Dozens of Alaskan rivers have turned bright orange in recent years because melting permafrost has released high levels of toxic metals into the waterways, a worrying new study reveals. The colorful contamination, which can be seen from space, is a potential ecological nightmare — and is likely to get even worse in the coming years, researchers say.

In the new study, which was published May 20 in the journal Communications Earth & Environment, researchers identified at least 75 orange rivers and streams in a Texas-size area of Alaska's Brooks mountain range. Most of the affected waterways were initially spotted by helicopter surveys of the area.

"The more we flew around, we started noticing more and more orange rivers and streams," study lead author Jon O'Donnell, an ecologist with the National Park Service's Arctic Inventory and Monitoring Network, said in a statement. "There are certain sites that look almost like a milky orange juice." 

Chemical analysis of the rusty rivers revealed high levels of zinc, nickel, copper and cadmium, as well as iron, which is largely responsible for the orange hue of the waterways. Researchers also found that the polluted waterways were unusually acidic: Some of the smaller streams had a pH of as low as 2.3, which is around the same as lemon juice or vinegar, according to the U.S. Geological Survey.  

The high metal concentration and acidity of the water can both be tied to melting permafrost — a permanently frozen layer of Earth's surface that covers large swaths of the Arctic. As the frozen ground thaws thanks to human-caused climate change, previously sealed minerals are exposed to rain for the first time in thousands of years, allowing metals to dissolve out of the rocks and into surrounding streams, which feed larger rivers.  

Not only are the affected habitats visually transformed but the high mineral concentrations are also highly toxic to most aquatic life. Researchers are particularly worried about what the toxic meltwater could be doing to spawning fish, which could have major knock-on effects on U.S. fisheries.

Related: US rivers are changing from blue to yellow and green, satellite images show

The idea for the new study was seeded back in 2018 when researchers visited a rust-colored river that had been crystal clear just a year earlier. However, subsequent satellite sleuthing revealed images of orange rivers dating back as far as 2008.

It is hard to tell how much metal has been released into rivers during this time. But the rivers in satellite photos "have to be stained a lot to pick them up from space," study co-author Brett Poulin, an environmental toxicologist at the University of California, Davis, said in the statement.

The researchers are planning follow-up tests this year to determine the full scale of the problem. However, they fear that increased permafrost melting caused by record-breaking temperatures over the last year will have released even more metals. And as temperatures continue to climb in the coming decades, metal contamination is likely to get even worse. 

As the water gets more acidic over time it will also make it easier for even more metals to dissolve from the newly thawed permafrost, creating a worrying "positive feedback loop" — where the problem gets exponentially worse. The melting of the permafrost is also likely to birth more new rivers in places like Alaska and Siberia, which would further exacerbate the issue.

There are lots of other serious implications to losing permafrost coverage, such as releasing more greenhouse gases into the atmosphere, as well as uncovering radioactive materials and unleashing dormant viruses, which could spark new pandemics. 

"Spacecraft dust" from defunct satellites burning up in Earth's atmosphere could weaken our planet's magnetic field, a controversial new paper suggests. 

In the worst-case scenario, the unchecked expansion of commercial satellite "megaconstellations" orbiting Earth, such as SpaceX's Starlink network, may generate enough magnetic dust to cut our planet's protective shield in half, potentially leading to satellite disasters and "atmospheric stripping," the paper's author told Live Science. 

But is this outcome really likely? Other researchers are skeptical of the paper's claims, though they all agree on one thing: there's an urgent need to quantify the scale of the problem.

Private satellites currently in orbit are a rapidly growing headache for astronomers due to their tendency to photobomb cosmic images and interfere with radio telescopes, as well as the increased risk of collisions with other spacecraft. But the real threat they pose may be what happens to them when they die.

When spacecraft end their missions, most are deorbited and burned up in Earth's atmosphere to minimize the amount of space junk circling our planet. However, as they fall apart in flames, the dying spacecraft litter our upper atmosphere with vaporized metal pollution.

Related: Sci-fi inspired tractor beams are real, and could solve a major space junk problem

In the new theoretical paper, uploaded to the pre-print database arXiv in December 2023 but not yet peer-reviewed, Sierra Solter-Hunt, a doctoral candidate at the University of Iceland, proposed that this atmospheric spacecraft dust may compromise the magnetosphere — the part of Earth's magnetic field that extends into space and protects the atmosphere from solar radiation.

Solter-Hunt is concerned that if satellite megaconstellations evolve as planned, the amount of dust they release may create a magnetic shield that could limit the magnetosphere's reach.

"I was shocked at everything that I found and that nobody has been studying this," Solter-Hunt told Live Science. "I think it's really, really alarming."

Accumulating dust

We currently have no way of monitoring the amount of spacecraft dust in the atmosphere, but based on the amount of space junk that has already burned up on reentry, we could have increased the amount of metallic particulate in the skies by a million-fold since the start of the space age, Solter-Hunt said. 

And Solter-Hunt estimated between 500,000 and 1 million private satellites could orbit our planet in the coming decades. When all these satellites eventually fall to Earth it could dramatically increase the amount of spacecraft dust in the atmosphere to billions of times its current level, she said. 

Related: How many satellites orbit Earth?

It is currently unclear where all of this spacecraft dust will eventually end up but Solter-Hunt thinks that it will probably settle in the upper part of the ionosphere — a region of the atmosphere between 50 and 400 miles (80 and 644 kilometers) above the surface. "And it could just stay there forever," she added.

Magnetic shielding

If all these proposed satellites go up in flames, the resulting spacecraft dust could create a "perfect conductive net around our planet" that could be capable of carrying an electric charge, Solter-Hunt said. If this happened, the magnetosphere, which normally extends thousands of miles into space, would be "distorted to stay under the conducting material," essentially limiting its reach to the upper ionosphere, she added.

A reduced magnetic field could expose satellites to high levels of radiation and solar storms, which could knock them out of the sky, Solter-Hunt said. "It's a real Catch-22 for satellite companies," she added. "They could be weakening the magnetosphere with what they're doing, which in turn puts themselves at risk."

But even if the magnetosphere doesn't shrink, the increased levels of spacecraft dust could still make it harder for rockets to launch new satellites and other spacecraft into space, Solter-Hunt said. This is because the magnetic particles could interfere with onboard electronics, she added.

Worst-case scenario 

In Solter-Hunt's worst-case scenario, increased levels of radiation bombarding the upper ionosphere could begin to blow away the outer edges of our atmosphere — a phenomenon known as "atmospheric stripping," which has naturally occurred on planets like Mars and Mercury. 

But this would be the "most extreme case" and may take centuries, if not millennia, to occur, she added.

Related: NASA and Japan to launch world's 1st wooden satellite as soon as 2024. Why?

But even if the atmosphere remains intact, spacecraft dust could still damage it.

Past studies have suggested that some of this pollution, particularly alumina (aluminum oxide), could deplete atmospheric ozone, potentially increasing the size of the ozone holes above Earth's polar regions.

The magnetosphere is also undergoing some natural weakening as the Earth's core grows and solidifies, and nobody knows if spacecraft dust could accelerate this process or not.  

'Important first step'

Some researchers praise the new paper for highlighting hidden potential issues of spacecraft dust. 

"This work is a really important first step" and highlights the "terrifying" amount of spacecraft dust that could be deposited in the atmosphere, Samantha Lawler, an astronomer at the University of Regina in Canada, told Live Science in an email. "The consequences [of this pollution] could also be on a totally different scale than we're used to thinking about," she added.

Related: SpaceX rockets keep tearing blood-red 'atmospheric holes' in the sky, and scientists are concerned

However, other experts think that the scenarios laid out by Solter-Hunt are too speculative or based on flawed assumptions. 

"Even at the densities [of spacecraft dust] discussed, a continuous conductive shell like a true magnetic shield is unlikely," John Tarduno, a planetary scientist and magnetosphere expert at the University of Rochester in New York, told Live Science in an email. Some of the assumptions in the paper are also "too simple and unlikely to be correct," he added.

In particular, no one has modeled how spacecraft dust will settle in the atmosphere, how long it will last or how conductive it will be, meaning there is no proof that magnetic shielding is possible, José Ferreira, a doctoral candidate at the University of Southern California who is also studying space dust pollution, told Live Science in an email. 

The number of potential satellites orbiting Earth in the future also "seems exaggerated," as many touted satellite launches never occur, Fionagh Thompson, a research fellow at Durham University in England who specializes in space ethics, told Live Science in an email. 

The paper is an "interesting thought experiment," Thompson added. But without clearly outlining exactly how spacecraft dust will cause these problems, "it shouldn't be passed off as 'this is what is going to happen'," she said. 

Solter-Hunt understands the researchers' criticism. However, due to the imminent rise in satellite launches, she wanted to share her theories with the scientific community. "I put it there so everyone can see it and talk about it," she said.

And, despite their reservations about this paper, the experts all agree that more research is urgently needed to study the possible effects of metal pollution in the atmosphere.

"This is not an issue to be ignored," Thompson said. "There is a need to step back and view this [space junk pollution] as a completely new phenomenon." 

"There's a desperate need to study this as fast as possible," Lawler added. "Honestly, I don't think anyone knows what could happen." 

People in the U.K. have volunteered to inhale diesel exhaust, cleaning products and cooking fumes to help unravel the effects of air pollution on the brain.

The study is being conducted by researchers affiliated with the University of Manchester and the University of Birmingham, as well as by health care providers from Manchester University National Health Service (NHS) Trust. The research team specifically recruited volunteers who were more than 50 years old and had a family history of Alzheimer's disease or another type of dementia.

There's a well-established link between exposure to air pollution and the risk of dementia, with regions with high concentrations of pollution seeing higher rates of dementia than less-impacted areas. However, scientists don't completely understand how the pollution might be driving changes in the brain.

"What we're trying to do in this study is to actually do experiments to understand why there's an association, to find out what the underlying biological mechanisms are that link air pollution to adverse effects on the human brain," Dr. Ian Mudway, an environmental toxicologist at Imperial College London, told BBC News.

Related: Could vaccines prevent and treat Alzheimer's disease?

According to a brief description of the trial, posted Dec. 14 to the preprint database medRxiv, the study participants will be exposed to four pollutants: wood smoke, diesel exhaust, cleaning products and cooking emissions. Clean air serves as a point of comparison. At present, there are 13 study participants, BBC News reported.

Each volunteer will be exposed to the pollutants one at a time, at separate sessions conducted over several months; the study protocol didn't specify the exact concentrations of the pollutants. During each exposure session, the volunteer will be exposed to either a pollutant or fresh air for one hour via a fitted mask with a tube that allows the substance to flow in. 

Neither the volunteers nor the researchers collecting data will know which pollutant a volunteer will be exposed to at a given session, to avoid bias. Before and after each exposure, the participants will complete a breathing test called a spirometry, have their blood drawn for testing and complete various cognitive tests. Volunteers are compensated for each session they attend, and they're monitored for signs of any side effects during the experiment, especially respiratory symptoms like shortness of breath.

The goals of the study are to identify some of the most hazardous components of outdoor and indoor air pollutants and to determine how they might drive degenerative processes in the brain. 

It's possible, for example, that the pollutants act on the brain directly, reaching brain cells via nerves in the nose or through the bloodstream. Alternatively, the pollutants might injure the brain indirectly by triggering widespread inflammation in the body that can then have secondary effects on the brain, the researchers wrote in their medRxiv report.

"At the moment we just don't know," Gordon McFiggans, a project lead and professor of atmospheric science at the University of Manchester, told BBC News. Although fairly small, the study is still one of the largest ever aimed at addressing this question experimentally in humans, rather than in animals, the BBC reported. Time will tell what its results reveal.

This article is for informational purposes only and is not meant to offer medical advice.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

The sky is littered with metal pollution from bits of space junk that burn up as they reenter the atmosphere, a new study reveals. This unexpected level of contamination, which will likely rise sharply in the coming decades, could change our planet's atmosphere in ways we still don't fully understand, researchers warn.

The study, published Oct. 16 in the journal PNAS, is part of the National Oceanic and Atmospheric Administration's (NOAA) Stratospheric Aerosol Processes, Budget and Radiative Effects (SABRE) mission, which monitors the levels of aerosols — tiny particles suspended in the air — within the atmosphere.

The team used a research plane, which was fitted with a specialized funnel on its nose cone that captures and analyzes aerosols to sample the stratosphere — the atmosphere's second layer that spans between 7.5 and 31 miles (12 and 50 kilometers) above the planet's surface. The study was designed to detect aerosols covered with "meteor dust" left behind by space rocks that burned up upon entry. Instead, the plane detected high levels of metallic elements contaminating the floating molecules, none of which could be explained by meteors or other natural processes.

The two most surprising elements were niobium and hafnium, which are both rare earth metals used to make technological components such as batteries. The researchers were also puzzled by high levels of aluminum, copper and lithium.

The team had not expected to find these elements in the stratosphere and were initially confused as to where they had come from, study lead author Daniel Murphy, an atmospheric chemist at NOAA's Chemical Sciences Laboratory in Boulder, Colorado, said in a statement. "But the combination of aluminum and copper, plus niobium and hafnium, which are used in heat-resistant, high-performance alloys, pointed us to the aerospace industry," he said.

Related: 15 of the weirdest things we have launched into space

The discovery "represents the first time that stratospheric pollution has been unquestionably linked to reentry of space debris," researchers wrote in the statement.

In total, the study identified 20 different metallic elements that do not naturally occur in Earth's atmosphere, including silver, iron, lead, magnesium, titanium, beryllium, chromium, nickel and zinc.

The team suspects that the main source of the pollution is rocket boosters that are ejected by rockets shortly after they clear the upper atmosphere, then fall back to Earth.

China, which was previously criticized for a series of uncontrolled reentries, is responsible for many of these rocket booster reentries. However, this problem has also plagued Russia and NASA.

Falling satellites that have been abandoned, knocked out of orbit by solar storms or purposefully crashed back to Earth are also likely to release large amounts of metal pollution as they burn up.

Pollution from satellites will likely increase as more commercial satellites are launched into space. Of particular concern is the nearly 9,000 satellites that are currently in low-Earth orbit, which are all destined to eventually fall back to Earth, according to Orbiting Now. 

In total, around 10% of aerosols from the new study were polluted with space junk metals. But the researchers predict that this could jump to around 50% in the next few decades. 

It is currently too early to tell what long-term effects this pollution will have on our planet. But past atmospheric pollution, such as chlorofluorocarbons (CFCs), contributed to holes in the ozone layer. Aerosols also play a role in reflecting sunlight back into space, which is important for mitigating the effects of climate change.

"A lot of work" will be needed to "understand the implications" of these metals in the atmosphere, Murphy said.

This year's hole in the ozone layer above Antarctica is one of the biggest ever seen, satellite data shows. Experts believe the huge gap in Earth's protective shield may have been caused by the eruption of Tonga's underwater volcano in early 2022. 

The ozone layer is a band of Earth's atmosphere between 9 and 18 miles (15 and 30 kilometers) above the surface, where there is a high concentration of ozone — a type of oxygen molecule with three atoms instead of two. The ozone layer blocks out harmful levels of ultraviolet (UV) rays from the sun, which is necessary for various life forms, including humans, to survive. 

In 1985, researchers discovered that large holes were appearing in the ozone layer above Earth's polar regions, and that chlorofluorocarbons (CFCs) — a common chemical used in aerosol cans, packing materials and refrigerators at the time — were reacting with the ozone in Earth's atmosphere, depleting ozone levels. This led to the international community banning CFCs in 1989, allowing ozone levels to recover over time. 

However, gaps in the ozone layer still form above the polar regions during each hemisphere's winter months when cold air creates polar stratospheric clouds (PSCs) — extremely high clouds made from tiny ice crystals that sometimes appear to be rainbow-colored — which further deplete the already limited amount of ozone above the poles.

This year's ozone hole above Antarctica reached its maximum size on Sept. 16 when it peaked at a whopping 10 million square miles (26 million square kilometers), according to the European Space Agency (ESA), which monitors the hole with the Copernicus Sentinel-5P satellite. That is around the same area as North America, three times the size of Brazil, the equivalent of Russia and China combined or around twice the size of Antarctica itself.

Related: Claims of new 'tropical ozone hole' raise controversy 

"The 2023 ozone hole got off to an early start and has grown rapidly since mid-August," Antje Inness, a researcher at the European Center for Medium-Range Weather Forecasts, said in the statement. It is "one of the biggest ozone holes on record," she added.

The enormous gap could be attributed to the eruption of the Hunga Tonga-Hunga Ha'apai volcano, which exploded with the force of more than 100 Hiroshima bombs and created the tallest-ever recorded eruption plume when it popped its top in January 2022, researchers said. 

In August 2022, a separate group of scientists warned that the eruption could destabilize the ozone layer after more than 50 million tons of water was launched into the upper atmosphere, which is equivalent to a 10% increase in the amount of atmospheric water. The scientists suggested the water vapor could further destabilize the ozone layer after breaking down into ions, or charged molecules, that react with ozone in a similar way to CFCs. Water vapor also increases the chance of PSCs forming in polar regions, according to ESA.

Related: Did the Tonga eruption cause this year's extreme heat?

It now appears that those scientists were right, Inness said. But further research is needed to confirm the link between this year's ozone hole and the eruption, she added.

The ozone holes above both poles display natural variability that could also play a role in this year's giant cavity. In 2019, Antarctica's ozone hole shrunk to its smallest size on record, due to unusually warm temperatures that prevented PSCs from forming. But from 2020 to 2022, the ozone hole grew in size year on year as colder temperatures returned. 

This year's El Niño event may also have played a small role in altering temperatures around the poles, but this relationship is unclear at present.

Although the current ozone hole is one of the largest ever seen, there is no reason to panic, ESA researchers said. The area below the ozone hole is largely uninhabited, and it should fully close up again within a few months. If CFC levels remain low, then the ozone layer should be fully healed by 2050, they added.

For a day or two during wildfire season, cities like New York, Chicago, San Francisco, Sacramento and Seattle earn the dubious title of worst air quality in the world, according to real-time data from air sensor company IQAir.

But most of these cities don't typically have such polluted air. So which cities regularly have the worst air quality, and why?

Air pollution is often measured in terms of the concentration of particulate matter (PM), or a mix of solid and liquid droplets suspended in the air. Hundreds of cities have air year-round that the U.S. EPA considers unhealthy for just one day, according to the World Health Organization's (WHO) most recent data on PM2.5 small particle pollution, or those inhalable particles smaller than 2.5 micrograms.

An IQAir report found that Lahore, Pakistan had the worst air quality in 2022. Hotan in China ranked number two, followed by a suburb of Delhi, India. In 2021 the top three most polluted cities were in India; among the world’s capital cities, Delhi ranked first, then Dhaka, Bangladesh and N'Djamena, Chad. These cities all averaged more than 90 micrograms per meter cubed of PM2.5 over the course of the year, or nearly 20 times the recommended level.

Related: Even brief exposure to diesel exhaust alters activity in key brain network, study finds

Despite these rankings revealing some air pollution hotspots, it's impossible to determine which cities really have the worst air. The sensors used vary in quality, while many countries in Africa don't appear on the list because they don't report any data at all. The WHO uses only high-quality sensors, but it does not even try to rank cities: A spokesperson told Live Science that collection procedures vary too widely.

Even the metric being measured, PM2.5, has limitations. Inhaling small particles can cause health problems, and very few cities meet the WHO's most stringent PM2.5 guideline. But the chemical composition of these particles may also impact health. A WHO spokesperson said that research is not conclusive, but it is possible that cities with the same PM2.5 levels overall might have different health outcomes depending on the source of pollution.

There are several reasons why some cities have more PM2.5 than others. One is geography. Hotan is near the Taklamakan desert and experiences frequent dust storms. N'Djamena, likewise, is near the southern edge of the Sahara Desert. Mountains can impact air quality by making it harder for pollutants to disperse: Delhi, Lahore, Dhaka, and many other cities with unhealthy air lie just south of the Himalayas.

In Delhi, for instance, "just touch anything and you will have the dust, even if you clean every day," said Umesh Kulshrestha, the former dean of the School of Environmental Sciences at Jawaharlal Nehru University in New Delhi. Infrequent rain outside of the monsoon season helps dust accumulate — not only from far-off deserts, but also from unpaved roads and construction work in Delhi itself.

In addition, Delhi’s PM2.5 pollution also comes from fossil fuels. Fossil fuels harm air quality in cities worldwide. Indirectly, they increase global temperatures, which means more wildfires burn and more green spaces become deserts. Both those processes add PM2.5 to the air. Emissions from vehicles, power plants, and industrial sources also directly pollute cities locally. In a review in the journal Aerosol and Air Quality Research, Kulshrestha found that during the pandemic lockdowns in early 2020, Delhi's air quality improved, with its index score going down by 41%, thanks to reduced vehicle and industrial emissions.

Kulshrestha told Live Science that in South Asia, other common PM2.5 sources include brick kilns, crop burning, and the biofuels that many households still rely on for cooking and heating. He said that India is working to increase renewable energy sources and to replace biofuels with liquid natural gas — while this contributes to global warming, it can lower household PM2.5.

The U.S. remains the world's second-largest consumer of fossil fuels after China, contributing to poor air quality worldwide. Decades ago, though, persistent smog trapped in California's Los Angeles Basin prompted the Clean Air Act, which has since improved air pollution across the U.S.

Likewise, today's most polluted cities are also taking action to protect their skies. In Dhaka, bans on inefficient, highly-polluting two-stroke engines in three-wheeled vehicles helped keep PM2.5 levels from vehicle emissions steady as the city grew. Even though many Chinese cities are among the most polluted, there has been a dramatic decrease in pollution over the past decade since the country implemented clean air policies. In Delhi, Kulshrestha is pushing to create artificial lakes. More water should mean more evaporation, more rain and — Kulshrestha's research predicts — at least a little less dust.

Editor's Note: This story was updated on Sept. 8, 2023 to note that Umesh Kulshrestha is former, not current dean of the School of Environmental Sciences at Jawaharlal Nehru University in New Delhi.

Nuclear weapons testing in the 1950s and early 1960s left the first obvious and indelible marks of "overwhelming" human activity on Earth, and these events may signal the beginning of a new geological epoch known as the Anthropocene, geologists say. 

Fallout from these tests snowed down from the atmosphere and became trapped in the earth as layers of sediment rich in a radioactive form of plutonium, called plutonium-239. 

Scientists argue that blankets of plutonium-239-rich sediment at the bottom of a small lake in Canada present the earliest tangible record of human activities shifting the balance of natural systems — which is why they're naming this potential new epoch "anthro" after humans.

"The presence of the plutonium mark is a simple tool to allow us to define that boundary," Colin Waters, an honorary professor at the University of Leicester in the U.K. and the chair of the Anthropocene Working Group (AWG), said in a presentation organized by Germany's Science Media Center on July 6. "Because of the above-ground nuclear detonation — the testing that went on in the 1950s — there's a very precise geochemical boundary that is present across the planet, across all environments, that links to the onset of those detonations."

Researchers first proposed a new geological epoch in the early 2000s, after the late Dutch meteorologist Paul Crutzen, who was awarded the Nobel Prize in Chemistry in 1995, coined the term "Anthropocene." This epoch marks the point where humans became the dominant influence on the global climate and environment.

Related: We are now living in a new geologic age, experts say

Crutzen set the boundary during the Industrial Revolution and argued that James Watt's design of the steam engine in 1784 marked a turning point.

But Crutzen's starting point for the Anthropocene is invisible outside of Europe, which was the center of industrialization in the 18th century, Waters said. "In the Southern Hemisphere there is no effect; the sediments just do not show any significant effect from the Industrial Revolution."

While the newly proposed boundary is visible in sediments all over the world, geologists with the AWG chose Crawford lake in Ontario to designate the end of the previous epoch, the Holocene, and the beginning of the Anthropocene.

Crawford lake formed 10,000 years ago when a limestone cave collapsed into underground waterways, forming a deep sinkhole, Francine McCarthy, a professor of earth sciences at Brock University in Canada and a voting member of the AWG, said in the presentation. This shape prevents the surface water from mixing with the bottom layers, meaning the lake acts as a funnel for particles raining down through the water column. In the warm summer months, particles of calcite from the limestone rocks crystallize and fall to the lake bed, where they form a white coating that contains information about the atmospheric and hydrospheric conditions in that year.

"It is that white layer that we can count and we can identify exactly each year we're looking at," McCarthy said. The record at Crawford lake indicates 1950 is the point when humans "overwhelmed" Earth systems, propelling an era that is "geologically different from before," she added.

The AWG's latest results are published in a special issue of the journal The Anthropocene Review.  

Editor's Note: The headline and lede of this story were updated on March 13, 2024 at 1:40 p.m. E.S.T. to remove reference to the total amount of plastic inhaled by humans every week. Researchers originally estimated that humans ingest a credit cards' worth, but this was a miscalculation; it's actually much lower than that.

Humans may be inhaling a staggering amount of toxic microplastic every week, and for the first time scientists have worked out where it ends up in your body.

In 2019, a team of scientists estimated that up to 16.2 bits of microplastic enter our airways every hour. Now, researchers have built on these findings to figure out how the plastic moves around our respiratory systems.

Microplastics are tiny chunks of plastic debris measuring less than 0.2 inch (5 millimeters) long, according to the National Oceanic and Atmospheric Administration (NOAA). These broken-down remnants of industrial waste and consumer goods are impossible to avoid; they can be found across the ocean and the atmosphere, inside bottled water and even in human poop.

Related: Monet and Turner's atmospheric landscapes actually depicted air pollution, new study finds

There have been few studies into how toxic microplastics impact human health, especially respiratory health. However, recent studies suggest these tiny particles could pose serious health problems. Now, researchers have used a computer model to find the regions of our airways most impacted by breathing in microplastics. The scientists published their findings June 13 in the journal Physics of Fluids.

"For the first time, in 2022, studies found microplastics deep in human airways, which raises the concern of serious respiratory health hazards,” first author Mohammad S. Islam, a senior research fellow at the University of New South Wales, Sydney, said in a statement.

The scientists built a computer model to analyze where the tiny chunks tend to travel inside our airways, and where they get deposited.

By analyzing this circulation under slow- and fast-breathing conditions with three possible plastic shapes (spherical, tetrahedral, and cylindrical), the researchers found that the biggest chunks of microplastic — those measuring about 5.56 microns (one-seventieth the breadth of a human hair) — were the ones most likely to get lodged. The places these larger chunks tended to go were in the upper airways, such as in the nasal cavity and the back of the throat.

The full health impacts of microplastics on the human body are still unknown. However, microplastics have been shown to kill human cells, and cause bowel inflammation and reductions to fertility in mice.

Microplastics can also carry viruses, bacteria and other hazardous chemicals, which hitchhike on the plastic’s microscopic surfaces.

The researchers say their next steps will be to investigate how the plastics are deposited inside human lungs, taking into account factors such as humidity and temperature. They noted that microplastics are becoming increasingly ubiquitous.

"Millions of tons of these microplastic particles have been found in water, air and soil. Global microplastic production is surging, and the density of microplastics in the air is increasing significantly," Islam said.

Editor's Note: This story was updated on June 25, 2025 at 8:40 a.m. E.S.T. to replace an image of credit cards, which may have added to the confusion as to the total amount of microplastics inhaled.

The smoke from wildfires in eastern Canada has reached all the way across the Atlantic Ocean to Norway, more than 3,000 miles (4,800 kilometers) away. 

Earlier this week, the haze crossed the Canadian border into the U.S., enveloping East Coast cities in smoke; New York City had the worst air quality of any major city in the world Wednesday (June 7). Throughout the week, wind has also carried this smoke across Greenland and Iceland into Norway, where it was first detected on Wednesday. However, the concentrations of smoke in Norway are "very weak," scientists from the Climate and Environmental Research Institute in Norway (NILU) told French news agency AFP. 

"When the smoke reaches Europe, the number of particles is much lower," Nikolaos Evangeliou, a senior scientist at the NILU, said in a statement. "This means that we can possibly see the smoke as a faint haze, and perhaps notice the smell of smoke. But the number of particles is so low that it should not cause any health hazards."

Low concentrations of smoke will likely drift across the Scandinavian country and into Southern Europe, according to NILU forecasting models, which pull data from the National Centers for Environmental Prediction's Global Forecast System in the U.S.

Related: How do wildfires start?

More than 9.4 million acres (3.8 million hectares) — roughly a quarter the size of New York state — have burned in Canada so far this year, Bill Blair, Canada's federal minister of emergency preparedness, said in a recent CTV news briefing, according to WXXI News, a public radio station based in Rochester, New York. That puts the country on target for its worst fire season ever, government officials say. 

"The distribution of fires from coast to coast this year is unusual," Michael Norton, an official from Canada's Natural Resources ministry, told Reuters. "At this time of the year, fires usually occur only on one side of the country at a time, most often that being in the west." 

Though pollution from these wildfires likely won't pose a health risk for people in Europe, high levels of smoke particulate matter in cities throughout the U.S. East Coast could cause respiratory issues, such as coughing and shortness of breath. As a result, health officials in New York City and Washington, D.C., are advising people in affected cities to limit outdoor activity until the smoke has dissipated to safe levels. 

Impressionist artists like Claude Monet and Joseph Mallord William (J. M. W.) Turner are famous for their hazy, dreamlike paintings. However, a new study finds that what these European painters were really depicting in their works wasn't a figment of their imagination, but an environmental disaster: air pollution.

Scientists examined approximately 100 artworks by the two impressionist painters, who dominated the art scene between the mid-18th and early 20th centuries, during the Industrial Revolution. The team discovered that what some art enthusiasts had long believed was Monet and Turner's style of painting was actually them "capturing changes in the optical environment" that were associated with a decrease in air quality as coal-burning factories began dotting European cities and spewing pollutants into the air, according to the study, published Jan. 31 in the journal Proceedings of the National Academy of Sciences.

"It is often said that Turner was born in the age of sail and died in the age of steam and coal — his lifetime spans a time of unprecedented environmental change," first author Anna Lea Albright, an atmospheric scientist with the Laboratory of Dynamic Meteorology in France, told Live Science in an email. "During the first Industrial Revolution, these large increases in air pollution were concentrated in London, which was known as the 'Big Smoke' [where Turner was based]. Monet painted later, in the second Industrial Revolution in London and Paris."

Related: Hidden Van Gogh self-portrait discovered under 'peasant woman' painting

For the study, the scientists focused on local sulfur dioxide emission levels in London and Paris during this time period and the ways air pollution can interact with light, such as by reducing the contrast of objects viewed against a background and by increasing the intensity or "whiteness" of an image, according to the study. 

They also determined that the artists' vision wasn't the cause of this trend toward hazier artworks. "Monet was not myopic; Turner did not have cataracts," a different group of researchers wrote in a 2016 study published in the journal Eye. 

"Over Turner and Monet's careers, I noticed that the contours of their paintings became hazier, the palette appeared whiter and the style transformed from more figurative to more impressionistic," Albright said. "We knew Turner and Monet were painting during the Industrial Revolution with its unprecedented environmental changes. Their stylistic transformations accord with physical expectations of how air pollution influences light."

Impressionist air pollution

Air pollution is caused when there's an increase in toxic microscopic particles in the atmosphere. The scientists likened air pollution in Paris and London during the Industrial Revolution to levels seen in modern megacities such as Beijing, New Delhi and Mexico City.

"Air pollution absorbs and scatters light, making objects at a distance look hazier," Albright explained. "By scattering background light of all wavelengths into the line of vision, the presence of air pollution gives images a whiter tint."

Those hazy, polluted scenes were then translated into some of Monet's and Turner's most renowned paintings, including Monet's "The Houses of Parliament, Sunset" (1903) and Turner's "Rain, Steam, and Speed - The Great Western Railway" (1844).

"Impressionism is often contrasted with realism, but our results highlight that Turner and Monet's impressionistic works also capture a certain reality," study co-author Peter Huybers, a professor of Earth and planetary sciences at Harvard University, told Live Science in an email. "Specifically, Turner and Monet seem to have realistically shown how sunlight filters through pollution and clouds.

"The idea that Impressionism contains certain elements of polluted realism highlights how connected we are to our environment," he added. "Our surroundings influence what we see, how we feel [and] what we focus on. Maybe a modern Turner or Monet would help us see other novel phenomena in our environment, like climate change."

The ozone hole that forms yearly over Antarctica has grown for the third year in a row. At nearly 10 million square miles (26.4 million square kilometers), the ozone hole is the largest it's been since 2015.

But despite that growth, scientists say that the hole's size is still on a downward trend overall.

"All the data says that ozone is on the mend," Paul Newman, NASA Goddard Space Flight Center's chief Earth scientist, told the Associated Press.

Ozone is composed of three oxygen atoms and makes up very little of our atmosphere, but it has a huge impact on our planet. The blanket-like layer stretching over the globe absorbs the most harmful ultraviolet (UV) radiation from the sun, shielding Earth's life. Ozone forms in the stratosphere, around 9 to 18 miles (14.5 to 29 kilometers) above Earth's surface. It forms when UV radiation splits regular oxygen molecules, which are made of two oxygen atoms (O2); the two free-floating oxygen atoms then each bond with an oxygen molecule, forming a molecule made of three oxygen atoms.

Scientists discovered the thinning ozone layer over Antarctica in the early 1980s. Although ozone is created and destroyed naturally in the stratosphere, human-driven pollution destroys ozone faster than it can form. In particular, industries that use chlorine or bromine, like refrigeration and air conditioning, destroy ozone at alarmingly high rates. In the stratosphere, chlorine molecules react with ozone to create one chlorine monoxide molecule (composed of a chlorine atom and an oxygen atom) and one O2 molecule. Then the chlorine monoxide molecule breaks down, freeing that chlorine atom to react with more ozone. According to the Environmental Protection Agency, one atom of chlorine can destroy 100,000 ozone molecules before that chlorine molecule is removed from the atmosphere.

Substances like chlorofluorocarbons, used in refrigeration and air conditioning, stay in the atmosphere for a long time — some for longer than six months — meaning the chlorine and other chemicals from these substances can wreak havoc on the ozone layer.

The ozone hole was first observed in the early 1980s and reached its largest extent in 2006, according to NASA. This year’s ozone hole, which peaked on Oct. 5, was the biggest recorded since 2015. But scientists aren’t too concerned.

"The overall trend is improvement. It's a little worse this year because it was a little colder this year," Newman told the AP.

A cold stratosphere is exactly what chemicals like chlorine need to break down ozone. During Antarctica's winter, the stratosphere gets cold enough for clouds to form. The ice crystals that make up those clouds provide a surface on which chlorine, for instance, can react with ozone. As spring approaches in September, the sun's UV rays jumpstart these reactions. Once summer is in full swing, the stratosphere warms up enough to evaporate the clouds, removing the surface on which ozone-destroying chemical reactions take place.

Global agreements like the Montreal Protocol, which regulates the production and consumption of ozone-depleting substances, have helped to repair the ozone hole. And despite the ozone hole's increasing size this year, scientists generally agree that the hole is shrinking.

Earlier this year the National Oceanic and Atmospheric Administration reported that ozone-depleting substances in the atmosphere have decreased by 50% since 1980. The report also noted that if this downward trend continues, the ozone layer could be fully repaired by 2070.

Jellyfish are swarming in massive numbers in the Mediterranean Sea, close to the port city of Haifa in northern Israel. The sea was "bedazzled with thousands of white dots," according to The Jerusalem Post, which also reported that the swarm extended below the surface to depths of several hundred meters.  

Officials with Israel’s Nature and Parks Authority (NPA) captured footage of the swarming nomad jellyfish (Rhopilema nomadica) in Haifa Bay on July 20 using aerial drones, and they shared the footage on the agency's website. The NPA also advised people against swimming in the area, due to the risk of painful jellyfish stings.

This unusually high concentration of jellyfish individuals, also known as a bloom, likely stems from human activities that may include pollution and climate change , NPA representatives said in a statement (translated from Hebrew).  

The explosion in jellyfish numbers this summer could have catastrophic consequences for the marine ecosystem near coastal Haifa, and could even affect industry and tourism, Ruthy Yahel, an NPA marine ecologist, said in the statement.

"We see great damage from it in many areas, such as ecological competition with the fish for food, economic damage, clogging of desalination plant pumps, cooling of power plants, damage to fishermen, and the public keeping their feet off the beaches because of the burning [from jellyfish stings]," Yahel said. (Remember: Despite the urban legend, don't treat jellyfish stings with pee, which can cause the jellyfish's stinging cells to release more venom. Instead, remove the tentacles with a tool — not your bare fingers — and splash something acidic, such as vinegar, on the wound, Live Science previously reported.)

Related: Scientists inserted disco 'strobe lights' into jellyfish to see how they function without brains

Jellyfish are a common sight off the coast of Israel during the summer, and large blooms were reported in 2015 and 2017, The Jerusalem Post reported. The University of Haifa maintains a website that tracks jellyfish swarms using reports from open water swimmers, divers, boaters, fishers, surfers, paddlers and kayakers. Its interactive map helps both fishing boats and beachgoers avoid areas of the ocean and beaches where jellyfish swarms have been spotted. 

Nomad jellyfish, currently the most common jellyfish species in waters near Haifa, are an invasive species that originated in tropical waters of the Indian and Pacific Oceans. Scientists suspect that the jellyfish invaded the Mediterranean from the Indian Ocean by using the Suez Canal — the artificial waterway in Egypt that connects the Mediterranean to the Red Sea through the Isthmus of Suez — CNN reported in 2015.

One possible cause for jellyfish blooms such as the recently-observed event, could be pollution; jellyfish may have flocked to this region in record numbers to escape sewage and dispersing solid waste that's pumped into the ocean, according to the NPA statement. Overfishing and population reduction in ocean animals that compete with jellyfish, such as sunfish, or that prey on them, such as sea turtles, could also explain why jellyfish are especially numerous this year, NPA representatives said.

Changing climate could also be playing a part in driving Haifa's jellyfish bonanza, Dror Angel, a marine ecologist in the University of Haifa’s Department of Maritime Civilizations, told The Jerusalem Post. "The past winter has been very rainy and cold at times. This may have affected the intensity of the blooms and their life cycle," Angel said. "We know for sure if there’s heavy rain, then lots of nutrients get washed into the sea. So there's more algae, plankton and more food for the jellyfish to eat."

Originally published on Live Science.

Fishers in Cambodia recently received a massive surprise when they reeled in a gigantic 400-pound stingray. The hefty ray was dragged up from the murky depths of the Mekong River after it swallowed a fish that had already been snagged on the fishers' line. 

The monstrous ray, which has been identified as a giant freshwater stingray (Urogymnus polylepis), was accidentally caught by locals on May 5 in the Stung Treng province in northeastern Cambodia. The fishers immediately alerted team members from the Wonders of the Mekong project — a conservation group run by the University of Nevada, Reno (UNR), in collaboration with local fishing authorities — who helped remove the fishing line and measure the ray before safely releasing it back into the river.

The massive specimen weighed a hefty 397 pounds (180 kilograms) and measured 6 feet (1.9 meters) wide and 13 feet (4 m) in length including its whip-like tail, which terminated in a 6 inch (15 centimeter) venomous, serrated barb, UNR representatives said in a statement.

Giant freshwater stingrays are the world's largest stingray species and "are contenders for the title of world's largest freshwater fish," Zeb Hogan, a UNR fish biologist and director of the Wonders of the Mekong project, told Live Science. 

Related: 7-foot 'monster' sturgeon found in Detroit River could be over 100 years old 

Little is known about these remarkably large fish because "catches are almost never reported," Hogan said, "which also makes it difficult to determine true abundance or population trends." 

However, past reports suggest that individuals can grow even bigger than this behemoth. "The size of this stingray was surprising," Hogan said. "But what's more surprising is that it's dwarfed by accounts of [individuals] twice the size reported by fishermen in the same area." 

The current record-holder for the largest fish in the Mekong River — which flows through China, Myanmar, Laos, Thailand, Cambodia and Vietnam — is a 646-pound (293 kg) Mekong giant catfish (Pangasianodon gigas) that was caught in Thailand in 2005, Hogan said. Giant freshwater stingrays can likely grow larger than this, he added. In 2009, a giant freshwater stingray caught in Thailand was estimated to weigh between 550 and 770 pounds (249 and 349 kg) but was never officially weighed. 

The largest freshwater fish in the world are beluga sturgeon (Huso huso); these enormous fish, which are found in Russia, can reach a maximum length of more than 26 feet (8 m) and weigh up to 2.2 tons (2 metric tons).

The Mekong River is also home to a number of other large aquatic species, including Irrawaddy dolphins, giant softshell turtles, Mekong giant catfish, giant barbs (a type of carp), giant goonch catfish and giant sheatfish (another type of catfish), according to the statement. "This remote and relatively pristine stretch of the Cambodian Mekong River appears to be the last place on Earth where all of these iconic giant freshwater species live alongside one another," Hogan said.

These giant species are able to grow to extreme sizes because the Mekong River has a wide variety of different habitat types including deep pools, braided channels, sand bars and islands that "provide refuge and space for the species to grow," Hogan said. Historically, the Mekong River is one of the "most productive rivers in the world" and would have provided an abundance of food for larger animals, he added.

However, the health of the Mekong River has seriously declined in recent decades due to water pollution, overfishing and habitat fragmentation due to river developments, such as dams, Hogan said. As a result, giant freshwater rays are now listed as endangered, according to the International Union for Conservation of Nature (IUCN) Red List of endangered species.

Originally published on Live Science.

Light pollution, or photo pollution, is the presence of excess artificial light and is the result of urbanization and industrialization. It is only one of the many forms of pollution on Earth, alongside plastic waste, greenhouse gases and sewage. 

Light pollution can have serious implications for our environment and even our health. Street lighting, domestic and commercial lights, vehicles and security lights all contribute to the creation of a dome-like shield of light pollution called skyglow, according to the International Dark-Sky Association. 

Along with skyglow, light pollution consists of glare, light trespass and clutter. Glare relates to light that can cause direct visual discomfort, whereas light trespass is light that escapes from sources such as bedroom windows. Clutter is the excessive grouping of lights. 

Light pollution can also be amplified by other types of air pollution, such as smoke and dust. This is because these types of pollution can scatter light in all different directions and brighten the sky even further.

Affects on astronomy and night vision

One of the immediate effects light pollution has on our environment is to obscure our view of the true night sky, according to telescope manufacturer Celestron. Without the presence of artificial light, the night sky is awash with celestial bodies, far away galaxies and constellations. However, if you’re looking up from the belly of a big city, you’d be unable to see many of these night sky objects.

Around 99% of people living in Europe and America live under skies that are almost 10% brighter than they would naturally be, according to the BBC. This also means that a large portion of the population doesn’t use the full potential of their eyes. 

The retina of the human eye can naturally adjust its light-sensing cells to acclimate to very low-light conditions, to allow some sort of night vision, according to the Duke University. But because of light pollution, 37% of people living in America don’t use their night vision, according to the BBC. 

To monitor and characterise light pollution, American astronomer John E. Bortle created the Bortle Dark-Sky Scale, which measures the brightness of the night sky at different locations. The scale measures our ability to observe celestial objects, such as planets and stars, under the interference of skyglow. 

Health risks

Other than depriving us of a starry star, there are many more implications to excess use of artificial light, such as throwing the human body's natural cycle out of whack.

Circadian rhythms are a group of physiological and neurological changes that occur in the body over a 24-hour-period. Collectively they’re also known as our body clock and is related to our sleep-wake cycle, according to Harvard University. 

Once the Sun has gone down and we are exposed to low light, our bodies naturally release a hormone called melatonin. Melatonin is released from the pineal gland in the brain and helps to increase tiredness and regulate sleep cycles, with peak production occurring in the early hours of the morning, according to the UK's National Heath Service (NHS). 

However, light pollution has been found to curb melatonin production in humans, even at low levels. This can result in disturbed sleep, impact our immune system and responses to stress. It has also been suggested that melatonin disruption by way of light pollution is connected to the increased risk of hormone-related cancers, such as breast or prostate cancer, according to journal Environmental Health Perspectives.  

The circadian rhythm doesn’t only affect humans, but most other living things. In studies of the European perch, researchers have found that even at the lowest light intensities disrupted melatonin production within the fish, according to the journal Environmental Pollution. 

Implications on wildlife behaviour

Along with health issues, light pollution can interfere with the behaviours of wildlife. Nocturnal predators such as bats are among the most affected by light pollution. These flying mammals are well adapted to hunting at night and actively avoid illuminated areas. 

Unfortunately, their insect prey is attracted to light sources, which leads to barren hunting grounds for bats, according to the Bat Conservation Trust. Also, when sources of artificial light are placed outside a bat's roost, it can prevent them from ever leaving and lead to them starving. 

While studying the reproductive cycle of wallabies, researchers have also found that births were weeks earlier among wallabies living near a lightly polluted area, such as a naval base, than those living in more rural areas, according to the Journal Proceedings of the Royal Society B. 

The study found that the use of outdoor light-emitting diodes (LEDs), which emit wavelengths in the blue spectrum of light, suppresses melatonin five times more than traditional outdoor light.

For newborn turtles, the presence of artificial lighting can make the difference between life and death, according to the Sea Turtle Conservancy. As turtle hatchlings emerge along sandy beaches, their natural instinct is to scurry to the ocean bathed in moonlight. However, street and commercial lights along the coast can confuse the hatchlings and cause them to move inland where they are often eaten or killed by car traffic.

Additional resources

For more information about light pollution, check out "The End of Night: Searching for Natural Darkness in an Age of Artificial Light" by Paul Bogard and "Fighting Light Pollution: Smart Lighting Solutions for Individuals and Communities" by The International Dark-Sky Association. 

Bibliography

• The International Dark-Sky Association "Light pollution", accessed April 2022. 
• John E. Bortle, "The Bortle Dark-Sky Scale", accessed April 2022. 
• Celestron, "What is light pollution and how does it affect views through my telescope?", February 2022. 
• Rebecca Morelle, "Light pollution 'affects 80% of global population'", BBC, June 2016.
• Duke University, "Eyes have a natural version of night vision", Science Daily, September 2018. 
• Samantha Tracy, "I Can’t Sleep… Can you turn off the lights?", Harvard University, accessed April 2022. 
• NHS, "Melatonin for sleep problems", accessed April 2022. 
• Angela Spivey, "LIGHT POLLUTION: Light at Night and Breast Cancer Risk Worldwide", Environmental Health Perspective, Volume 12, December 2010. 
• Franziska Kupprat, et al, "Can skyglow reduce nocturnal melatonin concentrations in Eurasian perch?", Environmental pollution, Volume 262, July 2020. 
• Bat Conservation Trust, "Lighting", accessed April 2022. 
• Kylie A. Robert, et al, "Artificial light at night desynchronizes strictly seasonal reproduction in a wild mammal", Proceedings of the Royal Society B, Volume 282, October 2015. 
• Sea Turtle Conservancy, "Information About Sea Turtles: Threats from Artificial Lighting", accessed April 2022. 

Plastic-eating bacteria could help to one day tackle some of the 14 million tons of plastic that is offloaded into our oceans every year. Plastic pollution leads to severe impact on marine ecosystems and can affect human health. For example, once plastic enters the ocean it can suffocate and entangle animals, according to the International Union for Conservation of Nature (IUCN). 

Microplastics are also ingested by many marine species that are both preyed upon by other species and that we catch for food. Once ingested, microplastics can leach the toxic contaminants that have collected on their surface into the body of the organism that has consumed it, according to the IUCN. 

Those toxins can accumulate and transfer up the food chain from marine life into humans, whenever we eat something that has been taken from the sea. On land, the majority of plastic ends up either building up in landfills or burnt into incinerators, which releases toxic fumes. Just 16% of all plastic produced is recycled to make new plastic, according to the BBC.

However, in 2016 Japanese scientists made a remarkable discovery that could help tackle the world's plastic problem, according to the journal Science. Scientists collected plastic bottles outside a recycling facility, and discovered that a species of bacteria was "eating" its way through them. Normally, bacteria spend their time absorbing dead organic matter, but Ideonella sakaiensis has developed a taste for a certain type of plastic called polyethylene terephthalate (PET). 

After analyzing the bacteria, the scientists found that it produced two digestive enzymes called hydrolyzing PET or PETase. When these enzymes interact with PET plastic it breaks down the long molecular chains into shorter chains (monomers) called terephthalic acid and ethylene glycol. These monomers are then broken down further to release energy for growth of the bacteria.

Following the discovery of plastic-eating bacteria, many genetic scientists have experimented with Ideonella sakaiensis to improve its efficiency. One such research venture has been to genetically engineer bacteria that are more efficient at enzyme production, such as E.coli, and turn them into PETase factories. 

Although the discovery offers hope in the fight against mounting plastic, scientists caution that we are still years away from widespread commercial use. Similarly, PETase only decomposes PET plastic, there are six other plastic types that we are still unable to degrade using enzymes. 

Super PETase

Researchers at the University of Portsmouth have re-engineered PETase to create an enzyme "cocktail" that they say can digest plastic up to six times faster than normal. The scientists combine PETase with another plastic-eating enzyme called MHETase to form one super enzyme, according to the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS). 

The combined PETase-MHETase enzyme was created with a synchrotron, a type of particle accelerator that uses x-rays 10 billion times brighter than the sun, according to the University of Portsmouth. It enabled researchers to see the individual atoms of each enzyme and draw their molecular blueprints. 

Scientists then stitched their DNA together to form a super enzyme. This enzyme can also break down Polyethylene furanoate (PEF), a sugar-based bioplastic.

Turning plastic into vanilla

Researchers at the University of Edinburgh have been using E. coli bacteria to convert plastic into vanillin, the primary component of vanilla bean extract. Considering that the global demand for vanillin exceeded 40,000 tons (37,000 metric tonnes) in 2018 and 85% is made from chemicals taken from fossil fuels, using plastic could be an eco-friendly alternative situation, as Live Science has previously reported. 

After degrading PET plastic into its basic monomers, researchers took the process one step further and converted one of those monomers, terephthalic acid, into vanillin through a series of chemical reactions. The resulting vanillin is believed to be fit for human consumption, though further investigation is needed. 

Additional resources

For more information about Earth’s plastic problem, check out the plastic pollution webpages of Greenpeace and WWF. If you’d like more information about how you could reduce your plastic use, check out "How to Give Up Plastic: A Guide to Changing the World, One Plastic Bottle at a Time" by Will McCallum and "How to Save the World For Free" by Natalie Fee. 

Bibliography

• IUCN, "Marine plastic pollution", November 2021
• Shosuke Yoshida, et al, "A bacterium that degrades and assimilates poly(ethylene terephthalate)”, Science, Volume 351, March 2016. 
• Ankita Maurya, "Enzymatic Remediation of Polyethylene Terephthalate (PET)–Based Polymers for Effective Management of Plastic Wastes: An Overview", frontiers in Bioengineering and Biotechnology, Volume 8, November 2020. 
• Brandon C. Knott, et al, "Characterization and engineering of a two-enzyme system for plastics depolymerization", PNAS, Volume 117, September 2020. 
• Rumiana Tenchov, "Can plastic eating super-enzymes solve our destructive plastic problem?", CAS, March 2021. 
• Katherine Latham, "The world's first 'infinite' plastic", BBC, May 2021. 
• Scott Carpenter, "The Race To Develop Plastic-Eating Bacteria", Forbes, March 2021. 
• University of Edinburgh, "Bacteria: Serving tasty solution to global plastic crisis" ScienceDaily, June 2021.
• University of Portsmouth, "New enzyme cocktail digests plastic waste six times faster", September 2020.
• University of Edinburgh, "Bacteria serves tasty solution to plastic crisis", June 2021. 

A once-in-a-century wave that pummeled a cargo ship in 1997 caused the worst toy-related environmental disaster of all time. As the vessel Tokio Express pitched and rolled near the United Kingdom's southwestern coast, 62 shipping containers tumbled off the ship — and one of them dumped nearly 5 million plastic Lego pieces into the ocean.

Soon after the event, which some referred to as the Great Lego Spill, beachgoers in Cornwall, U.K., began finding brightly-colored plastic Legos. Even now, 25 years after the Feb. 13 disaster, numerous Legos from the spill still appear on beaches in Cornwall.

Coincidentally, many of those sea-tossed Lego pieces were nautically-themed. There were tens of thousands of octopuses, life jackets, scuba tanks, diving fins and pirate cutlasses, along with terrestrial shapes such as flowers, "witches' brooms" and dragons, said British beachcomber and writer Tracey Williams, author of "Adrift: The Curious Tale of the Lego Lost at Sea" (Unicorn Publishing Group, 2022).

Related: How much plastic actually gets recycled? 

Williams began collecting beach Legos in 1997 in South Devon, U.K., soon after the spill; more than a decade later, she launched the Lego Lost at Sea Facebook group, where people shared photos of the Legos that they found on British beaches, Williams told Live Science.

"In 2010, I moved to Cornwall to be close to my family, and on my first trip to the beach I noticed Legos from the spill again," Williams said. "I was amazed that it was still washing up after all that time."

On that fateful day in 1997, the Lego bricks and objects had been loaded onto the Tokio Express in Rotterdam, the Netherlands, and they were bound for New York. But disaster struck about 20 miles (32 kilometers) off the coast of western Cornwall, in the form of a rogue wave, Cornwall Live reported in 2014.

For centuries, rogue waves — immensely tall and dangerous ocean waves that seemingly appeared out of nowhere — were thought to exist only in maritime legends. However, evidence in recent decades has shown that these waves do exist, though their unpredictability makes them difficult to track and study, according to the National Ocean Service (NOS). Also known as extreme storm waves, rogue waves are thought to form out of merging swells; the resulting wall of water can measure dozens of feet high and may rise suddenly and unexpectedly from a direction other than that of visible surface waves, the NOS says.

The captain of the Tokio Express described the Feb. 13 rogue wave as a "once in a 100-year phenomenon" that first rocked the ship 60 degrees in one direction and then 40 degrees in the opposite direction, according to the BBC. The ship's manifest listed 4,756,940 Lego pieces that were lost at sea, of which 3,178,807 were light enough to float, Cornwall Live reported. In 2015, the BBC mapped more than 40 beach locations in Cornwall where people had reported collecting wayward Lego bits. Williams and her family have probably collected thousands of Legos since the time of the spill, she told Live Science.

Beachcombers initially found the lighter-weight pieces, such as slippers, flowers, lifejackets and octopuses. Black and green dragons, which were also a common sight on beaches but were slightly heavier by comparison, may have also floated because they contained air pockets, Williams said.

"What we're finding now are the pieces that sank as well as the pieces that floated," she said. "It's providing us with an insight into what happens to plastic in the ocean, how far it drifts — both on the surface of the ocean but also along the seabed — and what happens to it as it breaks down." But one of the big problems with plastic pollution is that it can take centuries to degrade in the ocean, and as it deteriorates it releases chemicals that can harm animals' hormones and disrupt their reproduction, according to the American Chemical Society.

In fact, it may be even longer than a few hundred years until the lost Lego pieces break down. When scientists recently analyzed the structure of weathered beach Legos using  X-ray fluorescence, they found that it could take up to 1,300 years for Legos from the 1997 spill to degrade entirely, researchers reported in July 2020 in the journal Environmental Pollution.

Originally published on Live Science.

Astronomers have discovered never-seen-before rock types, made up of unusual ratios of minerals, within the remains of alien worlds ripped apart by their dying host stars. The research suggests that such exoplanets are built from a much wider array of materials than previously thought. 

In the new study, researchers looked at 23 white dwarfs — the small, dense remains of dead low- and medium-mass stars — within 650 light-years of the sun. As these stars were dying and transitioning into white dwarfs, they ripped apart their orbiting exoplanets. And so, the atmospheres of these white dwarfs contain the guts from the alien worlds they destroyed. Researchers worked out the ratio of different elements in the white dwarf atmospheres by analyzing the light given off by the stars; then, they calculated the most likely makeup of the minerals that would have formed the obliterated alien worlds.

The researchers found that only one of the white dwarfs contained the remains of exoplanets with a similar geological make-up to Earth. Within the rest of the dead stars, the researchers found the remains of exoplanets made of alien rocks never seen on our planet or the rest of the solar system. The rocks were so different from those known to science that the researchers even had to create brand new names to classify them. 

Related: 9 most intriguing Earth-like planets

"While some exoplanets that once orbited white dwarfs appear similar to Earth, most have rock types that are exotic to our solar system," lead author Siyi Xu, an astronomer at the National Optical-Infrared Astronomy Research Laboratory (NOIRLab) in Arizona, said in a statement. "They have no direct counterparts in the solar system."

Exoplanet graveyards 

White dwarfs form when main sequence stars, like the sun, run out of fuel to burn and begin to swell up into red giants before collapsing under their own weight into super-condensed and cooled stellar cores. During this process, these dying stars release a cloud of superheated gas that engulfs the planets that orbit them. 

Some exoplanets can withstand this cosmic barrage, but most get knocked out of their orbit and subsequently ripped apart by the white dwarf's strong gravitational field. This is known as tidal disruption; and once the planet is ripped apart, the white dwarf pulls the planetary remains inward in a process known as accretion. 

Normally, the atmosphere of a white dwarf contains only hydrogen and helium, because any heavier elements sink into the star's super-dense core. So, when the light the stars give off shows the presence of other heavier elements, researchers assume that those must come from exoplanet accretion.

Scientists have estimated that about 25% of all white dwarfs contain the remains of dead exoplanets or are so-called polluted white dwarfs. These exoplanet graveyards have become a hot topic of research among astronomers because scientists can use them to infer properties about the bodies that once circled them.

Reconstructing rock types 

In the new study, the researchers focused on polluted white dwarfs that already had precise measurement data showing their ratio of magnesium, calcium, silicon and iron in their atmospheres. Astronomers think these elements are common in the cores and mantles of exoplanets, which make up the majority of planets below the outer crust. By calculating the ratio of these elements, scientists can reverse-engineer the minerals that would have made up the planets' rocky guts. 

To do this, the researchers used a set of calculations that had previously "worked remarkably well" when used to "classify rocks on Earth" with similar data, co-author Keith Putirka, a geologist at California State University, told Live Science.

However, the results revealed that a "surprising" majority of the minerals that made up these exoplanets were very different from what they expected, Putirka said.

"On Earth, rocks that occur in the mantle consist of mostly three minerals, olivine, orthopyroxene and clinopyroxene," Putirka said. But the ratio of elements in most polluted white dwarfs showed that some of these minerals would have been unlikely to form, he added.

Instead, other minerals made up of different formulations of magnesium-rich periclase and quartz, which is a crystalline mineral made of silica — would have formed instead, which are different from those predicted within the other inner planets in the solar system, Putirka said. This goes against past assumptions that exoplanets would be more similar to those we see in the solar system.

These minerals are so different from those we know that the researchers had to create new names to classify them, including "quartz pyroxenites" and "periclase dunites." However, it is unclear exactly how many new minerals exist in these white dwarfs. "New experiments to fully understand the mineralogy of the new compositions" are required, Putirka said.

Interior vs. exterior 

In the past, studies into the atmospheres of polluted white dwarfs have focused on whether or not exoplanets were likely to have a continental crust like that of Earth. A continental crust, scientists think, is vital for sustaining life on a planet because it provides a stable structure for evolution to occur. The likelihood of exoplanets having crusts could therefore answer questions about the possibility of alien life or the chances of finding an Earth-like exoplanet.

In a paper published in February in the journal Nature Astronomy, researchers claimed to have found evidence of an Earth-like continental crust in the atmospheres of polluted white dwarfs. Like the newest study, this paper noted that a large part of the exoplanets' compositions was different from Earth's, Live Science previously reported. But rather than focus on the differences between the planets' overall compositions, the authors of that study focused on a specific set of elements as evidence to conclude the presence of continental crust. 

However, the authors of the new paper are not convinced. "We disagree that their identifications are valid examples of continental crust," Putirka said. Their assumptions rely too heavily on the presence of individual elements like aluminium and lithium, and not enough on the mineral they were from, he added.

The researchers also think that it may not even be possible to detect continental crusts within a polluted white dwarf because they make up such a small fraction of an exoplanet's mass. "Earth's crust is less than 0.5% of its total mass," Putirka said. "If planets are being assimilated wholesale into white dwarf atmospheres, it will be impossible to see crustal compositions."

But this doesn't mean that there is no hope in the search for continental crusts among exoplanets. Instead, the researchers believe that learning more about the minerals within a planet's mantle could tell them more about how likely it is that those worlds could have supported a crust or even plate tectonics, which are overlapping sections of a continental crust which move and collide with each other leading to earthquakes and volcanic activity. 

"If we have a mantle that contains no olivine but has quartz, or a mantle that contains no orthopyroxene but has periclase, the thermodynamic and physical properties could be quite different and could affect the type, thickness and extent of crust," Putirka said. "New experiments are needed to truly understand the kinds of geological histories that might be possible."

The study was published online Nov. 2 in the journal Nature Astronomy.

Originally published on Live Science.

A new NASA video highlights the giant ozone hole that opened over Antarctica this year.

A cold Southern Hemisphere winter, and possible effects of global warming, have caused the hole to grow to its 13th-largest extent since 1979. The ozone depletion you see in the NASA video is monitored by three satellites operated by NASA and the National Oceanic and Atmospheric Administration (NOAA): Aura, Suomi-NPP and NOAA-20. 

NASA released the new video of the Antarctic ozone hole's growth on Oct. 29. It is expected this year's hole will close no earlier than late November.

Related: 10 devastating signs of climate change satellites see from space

Ozone is a naturally occurring oxygen compound (which humans can also make) that forms high in the upper Earth atmosphere. The natural type of stratospheric ozone forms when ultraviolet radiation from the sun interacts with molecular oxygen in our atmosphere. The resulting ozone acts a bit like sunscreen, shielding the Earth's surface from ultraviolet radiation.

Unfortunately, chlorine and bromine produced from human activities erode the ozone as the sun emerges over the Antarctic after the polar winter, as the sun's radiation spurs erosion in that region. The 1987 Montreal Protocol restricts ozone-depleting substances among the nearly 50 abiding nations, but a majority of world nations are not signatories; at least some of that majority do not abide by the protocols.

Still, NASA said the protocol has been helpful. "This is a large ozone hole because of the colder than average 2021 stratospheric conditions, and without a Montreal Protocol, it would have been much larger," Paul Newman, chief scientist for Earth sciences at NASA's Goddard Space Flight Center, said in a statement.

This year's ozone hole reached a peak size of roughly the size of North America, or 9.6 million square miles (24.8 million square kilometers). Annual reduction of the ozone hole began again in mid-October, NASA noted. If the Montreal Protocol had not come into force, and assuming the atmospheric substance amounts of the early 2000s, the hole would have been larger by about 1.5 million square miles (about four million square kilometers), the agency added.

Back when the protocol was signed, scientists suggested the ozone layer would recover by 2060. But the recovery is slower than anticipated and the consensus now appears to be no earlier than 2070, Vincent-Henri Peuch, director of the European Union's Copernicus Atmosphere Monitoring Service, told Space.com in a recent interview.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom and on Facebook. 

During the COVID-19 pandemic, more than 28,000 tons (25,000 metric tons) of pandemic-related plastic waste, such as masks and gloves, have ended up in the ocean, according to a new study. 

That's more than 2,000 double-decker buses  worth of waste, The Guardian reported. And within a few years, a portion of those plastic gloves and packaging materials from pandemic purchases could be swirling around the North Pole.

The analysis found that 193 countries produced about 9.2 million tons (8.4 million metric tons) of pandemic-associated plastic waste from the start of the pandemic to mid-August 2021, according to The Guardian. 

The majority of the plastic — about 87.4% — was used by hospitals, while 7.6% was used by individuals. Packaging and test kits accounted for about 4.7% and 0.3% of the waste, respectively, the authors reported in a recent study, published online on Nov. 8 in the journal Proceedings of the National Academy of Sciences.

Related: Sea science: 7 bizarre facts about the ocean 

The team developed a model to predict how much of this plastic waste wound up in the ocean after being discarded. They predicted that, as of Aug. 23, about 28,550 tons (25,900 metric tons) of the plastic debris had already found its way into the oceans, transported there by 369 major rivers, according to The Guardian. 

In three years' time, the majority of the  debris will shift from the surface ocean to beaches and the seafloor, with more than 70% washing onto beaches by year's end, the authors wrote. 

While in the short-term, the trash will mostly impact coastal environments near its original sources, in the long-term, garbage patches may form in the open ocean, the model predicts. For instance, patches may accumulate in the northeast Pacific and the southeast Indian oceans. And plastic that gets swept toward the Arctic Circle will hit a dead-end, and much of it will then swiftly sink to the seabed, the model predicts. The researchers also predict that a so-called circumpolar plastic accumulation zone will form by 2025. 

And "at the end of this century, the model suggests that almost all the pandemic-associated plastics end up in either the seabed (28.8%) or beaches (70.5%), potentially hurting the benthic ecosystems," meaning the deepest regions of the ocean, the authors wrote.

"The recent COVID-19 pandemic has led to an increased demand for single-use plastic, intensifying pressure on this already out-of-control problem," the study authors wrote. "These findings highlight the hotspot rivers and watersheds that require special attention in plastic waste management." 

In particular, the study highlights a need for better systems for collecting, treatmenting and disposing of medical plastic waste in developing countries, to keep it out of rivers, and an overall need to limit the use of single-use plastics and increase the use of sustainable alternatives, where possible, the authors wrote. 

Read more about the new study in The Guardian. 

Originally published on Live Science.

Around 126,000 gallons (573,000 liters) of crude oil has spilled from a ruptured pipeline off the California coast and begun washing up on beaches and wetlands, along with several dead animals.

The U.S. Coast Guard reported the spill at 9 a.m. local time on Saturday (Oct. 2), after boaters noticed a sheen on the ocean surface, according to CNN. The oil slick now covers around 13 square miles (33.7 square kilometers) and has begun washing up on the shoreline between Huntington Beach and Newport Beach, causing widespread beach closures that could last for weeks or months, according to  Reuters.

"In a year that has been filled with incredibly challenging issues, this oil spill constitutes one of the most devastating situations that our community has dealt with in decades," Kim Carr, the mayor of Huntington Beach, told the Associated Press. She also described the spill as an "environmental catastrophe" and said that it could become a "potential ecological disaster."

Related: The 10 weirdest spills in nature

Officials believe the oil originated from a leak in an underwater pipeline connected to an offshore drilling facility owned by Beta Offshore, a subsidiary of Houston-based Amplify Energy. The company has shut off the pipeline and suctioned out all the remaining oil to prevent further spillage. The company also sent a remotely operated vehicle (ROV) to the site to determine exactly what went wrong, according to an Amplify Energy statement.

A wide-scale clean-up including both federal and state agencies is now well underway. "This response is currently a 24/7 operation and response efforts are scheduled to continue until federal and state officials determine that the response to the crude oil spill is complete," the U.S. Coast Guard told CNN.

However, there are fears that the spill could have wide-reaching implications for marine wildlife. Already, several dead oil-covered fish and birds have been confirmed in the area, with many more unconfirmed reports starting to come in, officials with the  City of Huntington Beach said in a statement.

Wildlife experts are also warning of long-term environmental problems as a result of the spill. "It has long-lasting effects on the breeding and reproduction of animals," Miyoko Sakashita, director of the Center for Biological Diversity’s oceans program, told AP News. "It’s really sad to see this broad swatch oiled."

Local conservationists are particularly worried about several protected wetland habitats in the area, which are home to numerous bird species, including the snowy plover (Charadrius nivosus) and the California least tern (Sternula antillarum browni), which are both listed as endangered under the Endangered Species Act, according to AP News.

"The oil has already infiltrated many of our wetlands in Huntington Beach and the Talbert area," Katrina Foley, an Orange County supervisor, told CNN. "And we want to do everything we can to prevent it from intruding into that area even further."

Around 2,000 feet (610 meters) of protective booms — floating barriers that contain oil spills — have been released at seven wetland locations in an attempt to limit the amount of oil that pollutes them, according to the City of Huntington Beach statement. 

The Coast Guard is also using absorbent booms to remove oil from the water's surface, but so far, only around 3,000 gallons of oil just 2.4% of the amount spilled, has been removed, according to Reuters.

The California Department of Fish and Wildlife has ordered a fisheries closure in waters up to six miles off the coast due to fears that oil may also contaminate seafood and cause public health problems, according to Reuters.

Originally published on Live Science.

Human society is on track for a collapse in the next two decades if there isn't a serious shift in global priorities, according to a new reassessment of a 1970s report, Vice reported

In that report — published in the bestselling book "The Limits to Growth" (1972) — a team of MIT scientists argued that industrial civilization was bound to collapse if corporations and governments continued to pursue continuous economic growth, no matter the costs. The researchers forecasted 12 possible scenarios for the future, most of which predicted a point where natural resources would become so scarce that further economic growth would become impossible, and personal welfare would plummet.

The report's most infamous scenario — the Business as Usual (BAU) scenario — predicted that the world's economic growth would peak around the 2040s, then take a sharp downturn, along with the global population, food availability and natural resources. This imminent "collapse" wouldn't be the end of the human race, but rather a societal turning point that would see standards of living drop around the world for decades, the team wrote.

Related: How much time does humanity have left?

So, what's the outlook for society now, nearly half a century after the MIT researchers shared their prognostications? Gaya Herrington, a sustainability and dynamic system analysis researcher at the consulting firm KPMG, decided to find out. In the November 2020 issue of the Yale Journal of Industrial Ecology, Herrington expanded on research she began as a graduate student at Harvard University earlier that year, analyzing the "Limits to Growth" predictions alongside the most current real-world data.

Herrington found that the current state of the world — measured through 10 different variables, including population, fertility rates, pollution levels, food production and industrial output — aligned extremely closely with two of the scenarios proposed in 1972, namely the BAU scenario and one called Comprehensive Technology (CT), in which technological advancements help reduce pollution and increase food supplies, even as natural resources run out.

While the CT scenario results in less of a shock to the global population and personal welfare, the lack of natural resources still leads to a point where economic growth sharply declines — in other words, a sudden collapse of industrial society.

"[The BAU] and CT scenarios show a halt in growth within a decade or so from now," Herrington wrote in her study. "Both scenarios thus indicate that continuing business as usual, that is, pursuing continuous growth, is not possible."

The good news is that it's not too late to avoid both of these scenarios and put society on track for an alternative — the Stabilized World (SW) scenario. This path begins as the BAU and CT routes do, with population, pollution and economic growth rising in tandem while natural resources decline. The difference comes when humans decide to deliberately limit economic growth on their own, before a lack of resources forces them to.

"The SW scenario assumes that in addition to the technological solutions, global societal priorities change," Herrington wrote. "A change in values and policies translates into, amongst other things, low desired family size, perfect birth control availability, and a deliberate choice to limit industrial output and prioritize health and education services."

On a graph of the SW scenario, industrial growth and global population begin to level out shortly after this shift in values occurs. Food availability continues to rise to meet the needs of the global population; pollution declines and all but disappears; and the depletion of natural resources begins to level out, too. Societal collapse is avoided entirely.

This scenario may sound like a fantasy — especially as atmospheric carbon dioxide levels soar to record highs. But the study suggests a deliberate change in course is still possible.

Herrington told Vice.com the rapid development and deployment of vaccines during the COVID-19 pandemic is a testament to human ingenuity in the face of global crises. It's entirely possible, Herrington said, for humans to respond similarly to the ongoing climate crisis — if we make a deliberate, society-wide choice to do so.

"It's not yet too late for humankind to purposefully change course to significantly alter the trajectory of [the] future," Herrington concluded in her study. "Effectively, humanity can either choose its own limit or at some point reach an imposed limit, at which time a decline in human welfare will have become unavoidable."

Read more about the report at Vice.com.

Originally published on Live Science.

Fish can get hooked on meth that washes into their freshwater homes, to the point that they actively seek out the stimulant, a new study suggests.   

After being used by humans, methamphetamine enters waterways through sewage systems and discharges from wastewater treatment plants. "Where methamphetamine users are, there is also methamphetamine pollution of freshwaters," first author Pavel Horký, an associate professor and behavioral ecologist at the Czech University of Life Sciences Prague, told Live Science in an email. 

Meth pollutes rivers all over the world, with concentrations of the drug ranging from a few nanograms to dozens of micrograms per liter of water, according to reports in the journals Chemosphere and Water. Given the global prevalence of meth in waterways, Horký and his colleagues wondered whether fish might get hooked on these small doses of the drug.

Related: 9 weird ways you can test positive for drugs 

The team's new laboratory study, published Tuesday (July 6) in the Journal of Experimental Biology, suggests that yes, even minuscule amounts of methamphetamine could be enough to cause addiction in freshwater fish, the team concluded.  

That said, an expert told Live Science that, even though the fish in the study sought out meth-tainted water, that may not be enough evidence to say they are truly "addicted." 

"I'm not sure you can truly say these fish are addicted to methamphetamine, but they certainly show a preference for the compound … which they shouldn't, really," said Gabriel Bossé, a postdoctoral research fellow at the University of Utah who was not involved in the study; Bossé uses zebrafish as a model to study complex brain disorders and recently developed a technique to study opioid-seeking behaviors in the fish. 

In regards to the new research, "it seems that the preference for meth dies down after just a few days," whereas if the fish were truly addicted, he'd expect that preference to persist over a longer period of time, he said. "Whether you call it addiction or not, you can argue, but it's clear that methamphetamine changed how these animals behave," and those effects could potentially hinder their ability to find food, avoid predators and reproduce in the wild, Bossé noted. 

In the new study, the team specifically focused on brown trout (Salmo trutta), which are native to Europe, western Asia and northern Africa and have been introduced to every continent except Antarctica, Horký said. The researchers placed 60 trout in a drug-free holding tank and another 60 in a tank laced with 1 microgram of meth per liter of water. 

The researchers had the latter group of fish soak in the meth-tainted water for two months — a step meant to simulate the effects of persistent drug exposure that might occur in a polluted river. The researchers then transferred the drugged fish into a clean tank for 10 days; if the trout had grown dependent on meth, they would begin to show symptoms of withdrawal after losing access to the drug, the team theorized. 

To test for these withdrawal symptoms, the team devised an experiment where fish could choose between swimming in clean water or water with trace amounts of meth; the tank is designed such that the two streams of water don't mix but the fish can still swim between them. When previously exposed fish showed a preference for the meth-tainted water in the experiment, that was taken as a sign of addiction to the drug, Horký told Live Science. 

The team ran select fish through this experiment on the second, fourth, sixth, eighth and 10th days after they'd been moved to the drug-free tank; they also ran drug-free fish through the same experiment, as a point of comparison. They found that, in the first four days after the tank swap, the meth-exposed fish showed a stronger preference for drugged water, compared with the fish that had not been exposed to meth. This difference waned the more time the exposed fish spent in the drug-free tank. 

The researchers also noted that, in general, the meth-exposed fish became somewhat sedentary in these first four days of withdrawal, while the drug-free fish swam about as usual. This lack of movement hinted that the fish were stressed out due to their meth withdrawal, the authors suggested; scientists have seen similar behavior in zebrafish that were experiencing withdrawal from opioids, according to a 2017 report by Bossé published in the journal Behavioural Brain Research.

To get better insight into these behavioral changes, the team took samples of the fishes' brain tissue and screened them for both methamphetamine and amphetamine, a metabolic byproduct of the drug. 

They found that "there were differences in concentration of amphetamine and methamphetamine that were shown to be related to changes in behavior," Horký said. The amount of amphetamine in the brain, which would indicate a past exposure to meth, correlated with the subdued swimming behavior seen in the trout experiencing withdrawal. Conversely, methamphetamine appeared in the brains of fish that chose to swim in the drugged water during the behavioral experiment; this acute exposure correlated with an uptick in swimming, again hinting that the meth offered relief from withdrawal in addicted fish.

Taken together, these results suggest that, in the wild, brown trout could become addicted to trace amounts of meth in rivers and potentially congregate in areas where the drug accumulates, the authors reported. Such "unnatural attraction to one area" could not only disrupt the fishes' migratory patterns but also undermine their success in foraging for food or finding mates, they wrote.

But again, while Bossé agrees that meth exposure could undermine the fishes' survival, he's not fully convinced the animals are addicted to the drug. The authors could strengthen their case with slight tweaks to their current experiment, he noted. 

Firstly, they could allow the fish more time to explore the tank with a meth-tainted section; given hours, instead of minutes, as in the current study, the fish might learn where the meth can be accessed and show more persistant drug-seeking behavior. Their preference for the meth-tainted water could even be tested over several days, to see if they consistently gravitate to the contaminated water after being denied access to the drug, he said.

In addition, the team could do additional tests to show the animals are truly in a stressed-out, withdrawal state; for example, they could measure the animals' cortisol levels and run them through formal stress tests, Bossé said. With zebrafish, these stress tests include observing what the fish do when placed in unfamiliar tanks or tanks with one darkened side, which the fish prefer, and one brightly-lit side.   

In any case, since the new study was conducted in a laboratory setting, the team still needs to investigate whether the observed patterns of addiction and withdrawal occur in wild fish populations, too, Horký said. There's also the question of how meth mingles with other contaminants in the water, including other drugs, like antidepressants, and how all these substances collectively mess with fish behavior, he noted. 

"There are a lot of contaminants of emerging concern — not only illicit drugs, but also standard prescription medicines, like antidepressants," Horký said.

Originally published on Live Science. 

A burning container ship dumped tons of plastic debris onto Sri Lanka's beaches, prompting a widespread environmental disaster, according to recent news reports.

The ship, the X-Press Pearl, had sailed to Sri Lanka from India and was anchored near Colombo on May 20, when the crew first reported smoke coming from their cargo hold, according to the X-Press Pearl Incident Information Center. On May 21, a fire started on deck and over the next week, the fire intensified and continued to spread. On May 24, the 13-person crew and 12-person firefighting crew were evacuated from the ship.

By May 31, with the help of the Sri Lankan Navy, firefighting tugs and the Indian coast guard, the fire was brought under control, with no visible flames remaining, but still some smoke, according to the Information Center. It's not yet clear how the fire started, but authorities are suggesting that a leak from the ship's containers sparked the flames, according to The Washington Post.

Related: Top 5 ways to reduce toxins in homes

The ship was carrying 327 tons (297 metric tons) of heavy fuel oil, 56 tons (51 metric tons) of marine fuel oil and 81 containers full of "dangerous goods," including 28 tons (25 metric tons) of nitric acid, a corrosive compound. The ship was also carrying three containers or 86 tons (78 metric tons) of plastic pellets, some of which fell off the ship and are now covering beaches down to the south coast of Sri Lanka, according to Mongabay.

Authorities are warning people not to touch the pellets, known as nurdles, as they can be contaminated with chemicals, according to Mongabay. Nurdles, which are the raw material used in making other plastic items, can absorb chemicals over time, and if marine species swallow them, they can contaminate the food chain.

"It's an environmental disaster," and currents can carry the pellets as far as the other side of Sri Lanka, potentially killing wildlife and damaging ecosystems, marine biologist Asha de Vos told the Post. Vos described the beaches as being filled with piles of plastic "snow."

Authorities have also temporarily banned fishing in these areas; and the National Aquatic Resources Research and Development Agency is sampling and analyzing dead fish and turtles found along the western coast to see if their deaths are related to the spills.

Sri Lanka's Marine Environment Protection and military personnel are working to remove the nurdles from the beaches before the pellets wash back into the water. Crews are temporarily dumping them into a hazardous waste yard and once scientists analyze the pellets , authorities will destroy them, according to Mongabay.

The cleanup will likely be challenging, Muditha Katuwawala, coordinator of the Pearl Protectors, a nonprofit organization that sends volunteers to clean beaches, told Mongabay. "We foresee that the cleaning process will be a lengthy operation, so we started creating tools that can assist the cleaning operations and to create awareness around beach pollution of such magnitude."

Because of a nationwide COVID-19 lockdown in Sri Lanka, Pearl Protectors hasn't been able to clean up after this incident, according to Mongabay. 

Originally published on Live Science.

The sea bottom near southern California has been hiding a very dirty secret: decades of discarded chemicals in thousands of barrels. And the toxic debris field is even bigger than anyone expected, containing at least 27,000 drums of DDT and industrial waste, scientists recently discovered. 

High concentrations of DDT (dichlorodiphenyltrichloroethane, an insecticide that was widely used for pest control during the 1940s and 1950s) were previously detected in ocean sediments between the Los Angeles coast and Catalina Island, in 2011 and 2013. At the time, scientists who searched the seafloor in the area identified 60 barrels (possibly containing DDT or other waste) and found DDT contamination in sediments, but the full extent of the area's contamination was unknown. 

Now, a research expedition presents a clearer picture of the deep-sea dump site. Their findings reveal a stretch of ocean bottom studded with at least 27,000 industrial waste barrels — and possibly as many as 100,000, researchers with Scripps Institution of Oceanography at the University of California said in a statement. 

Related: 10 of the most polluted places on Earth

From March 10 to March 24, a team of 31 experts onboard the Scripps research vehicle Sally Ride created high-resolution acoustic maps of the seafloor at the San Pedro Basin, covering 36,000 acres (146 square kilometers) from 12 miles (19 kilometers) off the coast of southern California to 8 miles (13 km) from Catalina Island. Two underwater autonomous vehicles (AUVs) named REMUS 6000 and Bluefin swam through depths up to 3,000 feet (900 meters) below sea level, using sonar to pinpoint the locations of the barrels. 

These containers were quite small — less than 3 feet (1 m) tall — and those that were buried looked even smaller in the sonar scans, expedition member Sophia Merrifield, a Scripps oceanographer and data scientist, said at a virtual news conference on April 27. The researchers therefore had to develop algorithms that would automate the process for identifying and counting such tiny objects, Merrifield explained.

"We needed to be able to pump hundreds of gigs [gigabytes] through an algorithm that would detect these very small, very bright targets," she said.

Images of the 60 sunken barrels spotted in 2011 and 2013 helped the scientists calibrate their algorithms. The result categorized not only an object's location but also its size and brightness, "so that we can do further pattern analysis and classification of the types of targets," Merrifield said.

From the AUV scans and data analysis, the expedition scientists discovered that more than 90% of the survey area contained some debris, Eric Terrill, chief scientist of the expedition and director of the Marine Physical Laboratory at Scripps, said at the news conference. Researchers found 100,000 pieces of human-made debris and identified the subset that were likely barrels holding DDT and other types of industrial waste, Terrill said.

"Irreversible damage"

This accumulation of seafloor dumping didn't happen overnight. While Los Angeles today is mostly associated with Hollywood and moviemaking, oil and gas were once thriving industries in the area, and much of the waste from extraction and processing wound up in the ocean, Terrill said at the press event.

"The dumping of industrial rate waste in the ocean actually began in the '30s and continued all the way into the early '70s," Terrill said. 

Companies also dumped byproduct waste from agricultural DDT manufacturing in the sea, and in 1985 the Los Angeles Water Quality Control Board released a troubling report describing "decades of systematic neglect" in official oversight of toxic waste disposal, "with the result being irreversible damage to the marine environment," the Los Angeles Times reported that year.

According to estimates, companies dumped between 386 and 772 tons (350 and 700 metric tons) of waste at offshore locations in the San Pedro Basin over nearly four decades, Terrill said. But it was unknown how extensive the dumping was, where exactly it happened, and if the containers holding the waste were leaking (and how much). 

A nearby location in the Palos Verdes Shelf is already recognized as highly contaminated with DDT and PCBs (polychlorinated biphenyls, another toxic industrial compound) and is designated as a Superfund site — a location so permeated with hazardous waste that it has been targeted by the Environmental Protection Agency (EPA) for cleanup, Terrill said. 

Related: Sea science: 7 bizarre facts about the ocean

Vital clues came to light in 2011 and 2013, when David Valentine, a professor of Earth science and biology at the University of California Santa Barbara's Marine Institute captured remote camera images of 60 industrial waste barrels on the seafloor, describing the toxic mess in a study published in 2019 in the journal Environmental Science and Technology.

Then, in October 2020, investigative reporting by the L.A. Times dug up damning details about DDT dumping. Shipping logs from the Montrose Chemical Corporation of California — the largest manufacturer of DDT in the U.S., based in Los Angeles from 1947 to 1982 — noted that thousands of barrels containing DDT were transported monthly and discarded in the deep sea near Catalina. In later years, crews began dumping the barrels closer to the California coast.

They also took other measures to speed up the work. "When the barrels were too buoyant to sink on their own, one report said, the crews simply punctured them," the L.A. Times reported.

While the research team doesn't yet know how many of the 27,000 newly-described barrels hold DDT, the survey offers a starting point for investigating the containers' environmental impact. The team's discoveries have already prompted California Senator Dianne Feinstein to request that the EPA "prioritize urgent and meaningful action to remediate this serious threat to human and environmental health," in a letter to the agency penned on March 12.

The scientists plan to analyze the data from the R/V Sally Ride expedition for a future peer-reviewed study, but releasing these initial findings (first in March, then in more detail on April 26) calls attention to the scope of the dump site and the threats it may pose to ocean ecosystems and marine life, the scientists said. 

"Putting this out now as a way to get information to policymakers and for other efforts," Merrifield said.

"We are hopeful the data will inform the development of strategies to address potential impacts from the dumping," Terrill added.

Originally published on Live Science.

Millions of tiny pieces of plastic are swirling around in Earth's atmosphere and traveling across entire continents, according to a new study. This environmental problem is likely to get much worse and could have serious effects on human health, experts say.

Microplastics measure less than 0.2 inches (5 millimeters) long, according to the National Oceanic and Atmospheric Administration (NOAA). And previous studies had shown that these microscopic particles can be found in the ocean, bottled water and even our poop, but until now, the atmospheric section of this "plastic cycle" had been poorly understood.

The new study revealed thousands of tons of microplastics already in the atmosphere, with roads as the biggest contributor. Computer modeling also revealed how particles get transported vast distances across the globe and showed that nowhere is safe from the pollution.

Related: 8 ways that air pollution can harm your health

The researchers said their findings highlight that microplastics are one of the most pressing environmental issues of our time.

"Microplastics have the capacity to disrupt nearly every ecosystem, not to mention human health," lead author Janice Brahney, an environmental scientist at Utah State University, told Live Science. "We are really only starting to understand the scope of the pollution, never mind the impacts."

In terms of importance, the issue is right up there with climate change and is somewhat intertwined with it, "since plastics are a product of fossil fuels," Brahney said. 

Entering the atmosphere 

To figure out how microplastics are being transported into and across the atmosphere, Brahney and her colleagues measured the fallout of particles from the air, as a result of both gravity and rain, at sites across the western United States over a 14-month period. Based on their findings, they estimated that around 1,100 tons (1,000 metric tons) of microplastics are in the atmosphere above the western U.S.

The team was "absolutely shocked" by the levels of microplastics they found, Brahney said.

The researchers had predicted that cities would be the largest source of atmospheric microplastic pollution, but the analysis of the plastic showed that roads were the biggest culprit, responsible for 84% of atmospheric microplastics.

"When you consider that plastic, like dust, needs to enter the atmosphere from some physical force, this makes more sense," Brahney said. "Roads — and, more importantly, cars driving on roads — provides the mechanical energy to move particles into the atmosphere."

Other sources included the oceans (11%) and agricultural soil dust (5%), both of which involved strong winds pushing particles into the air. However, the researchers suspect that all three of these sources will likely contribute to differing levels of pollution in other parts of the world.

Circling the planet

Using the data they collected, the researchers created computer models to figure out how microplastics are transported across the planet and which areas are likely hotspots for the highest levels of microplastics, such as Europe, Eastern Asia, the Middle East, India, and the United States.

"The atmosphere is one of the reasons why microplastics are so widespread," Brahney said. "It has the potential to transport plastics to disparate locations, across continents and to really remote locations that would otherwise be untouched by human pollution."

The researchers discovered that the plastic particles could remain in the air for between one hour and 6.5 days. That upper limit is enough time for cross-continental transportation, which means even places like Antarctica are at risk of pollution despite having no direct sources of plastic.

"No one is protected from this source of pollution," Brahney said. "We can ship our garbage to other countries, but it will just come back to haunt us."

Next steps

The issue of microplastics in the atmosphere is also likely to get much worse.

"Plastic needs some time to break down into the tiny fragments we see in the atmosphere," Brahney said. "Since we don't have effective means for handling plastic waste, and the problem is compounding, it may be that more plastics end up in our environment in the future and, therefore, our atmosphere."

Another important avenue of research, Brahney said, is to figure out how airborne plastics can affect human health. 

"Inhaling any particle can have negative health consequences," Brahney said. "But at present, we don't know whether plastics are more or less harmful than other natural aerosols."

The study was published online April 12 in the journal Proceedings of the National Academy of Sciences.  

Originally published on Live Science.

Late last week, a significant breach in the wall of a wastewater reservoir in Piney Point, Florida, threatened to spill hundreds of millions of gallons of tainted water into nearby communities.

The water contains high levels of phosphorus and the nitrogen, which can affect water quality, and should the reservoir completely collapse, the ensuing flood would surge through local homes and businesses and could potentially become contaminated by radioactive waste materials stored at the reservoir site, the Bradenton Herald reported. 

To prevent this potential disaster, officials began pumping wastewater out of the reservoir and into Port Manatee, a seaport that lets out into Tampa Bay, the Tampa Bay Times reported. The pumping began on March 30, and by April 4, an average of 35 million gallons (132 million liters) of water was being dumped into the bay each day. The water being dumped is not radioactive.

The plan is to completely drain the reservoir into the bay and into "large storage containers," Acting Manatee County Administrator Scott Hopes said April 4, according to the Tampa Bay Times. 

"We're not out of the critical area yet," Hopes said. Should the reservoir collapse, "all of the models show it would take less than an hour for it to drain out, in as high as a 20-foot [6 meters] wall of water," he said.

Related: Lessons from 10 of the worst engineering disasters in US history

What's in the water? 

Officials originally reported a leak in one of the ponds at the Piney Point reservoir on March 26, when they found water flowing from the pond at a rate of 2 million to 3 million gallons (8 million to 11 million liters) per day, according to The New York Times. The 79-acre (32 hectares) pond mostly holds salt water that was dredged from Port Manatee, as well as rainwater, stormwater runoff and "process water" from the now-defunct Piney Point phosphate plant, the Bradenton Herald reported. 

The phosphate plant originally opened in 1966 to manufacture fertilizer, and it operated for 35 years, according to the Herald. The fertilizer manufacturing also produced a waste product called phosphogypsum, which contains radioactive materials, including uranium and radium. 

The leaking wastewater pond sits atop a "stack" of this phosphogypsum, and although the water itself is not radioactive, a sudden breach of the reservoir wall could topple the stack underneath and send radioactive material streaming into nearby communities and waterways.  

The leaking pond also sits near two additional wastewater reservoirs, according to the Tampa Bay Times; should the leaking pond collapse, some experts worry that the freed water would wash over these nearby ponds and release hundreds of millions of additional gallons of contaminated water.    

The wastewater from the leaking pond "meets water quality standards for marine waters, with the exception of pH, total phosphorus, total nitrogen and total ammonia nitrogen," the Florida Department of Environmental Protection announced, according to The New York Times. "It is slightly acidic, but not at a level that is expected to be a concern, nor is it expected to be toxic."

On March 26, the leaking pond held 480 million gallons (1.8 billion liters) of water, The New York Times reported; by April 3, only 390 million gallons (1.5 billion liters) remained. Engineers attempted to plug the leak on April 2 and 3 but did not succeed. 

Upon closer examination, the engineers noted that "a portion of the containment wall at the leak site shifted laterally, signifying that structure collapse could occur at any time, and so staff and personnel were evacuated from the site," Jacob Saur, the county's director of public safety, told the Tampa Bay Times. 

On April 3, Florida Gov. Ron DeSantis declared a state of emergency, which established a mandatory evacuation zone around the reservoir. More than 300 homes — as well as farmland, pastures and a natural gas plant that supplies millions of Manatee County residents with power — fall within the evacuation zone, according to the Tampa Bay Times. The Manatee County jail is also in the flood zone, but not all staff and inmates are being evacuated; some are just being moved to higher floors of the jail.

"Looking at the volume of the water that has been removed and the current stability of the current breach, I think the team is much more comfortable than we were yesterday," Hopes said Sunday (April 4), according to the Bradenton Herald. "With the addition of the pumps ... I think we're going to be in an even better position." As of April 4, less than 300 million gallons (1.1 billion liters) of water remained in the leaking pond, the Tampa Bay Times reported.

Although the wastewater from the leaking pond is not expected to be toxic, the sudden infusion of phosphorus and nitrogen into Tampa Bay could wreak havoc on local plants and wildlife.

For example, pollutants from lawn fertilizers, septic tanks and agricultural waste have fueled algal blooms in the Indian River Lagoon, an estuary on Florida's Atlantic coast, coating the water's surface with muck that prevents light from reaching seagrasses below, National Geographic reported. When those seagrasses died, it caused a ripple effect through the entire ecosystem and left manatees with too little food to survive. 

In the wake of the Piney Point disaster, "algae blooms followed by fish kills are the most likely thing," Matthew Pasek, a geoscience professor at the University of South Florida, told Axios. "It's going to impact the food chain further down the line, too. It's unlikely to cause human damage, but there's going to be a pretty stinky bay for a while."

The Piney Point reservoir has leaked several times in the past, according to the Bradenton Herald. In 2003, about 250 million gallons (950 million liters) of wastewater was dumped into the Gulf of Mexico to prevent an overflow at the reservoir, and in 2011, a pond breach sent a surge of wastewater into Bishop Harbor.

Originally published on Live Science.

In 2016, European Space Agency astronaut Tim Peake shared a photo of a quarter-inch dent gouged into a glass window of the International Space Station (ISS). The culprit? A tiny fleck of space junk. 

The piece of debris, perhaps a paint flake or a metal fragment from a satellite, was only a few thousandths of a millimeter across — not much bigger than a single cell of E. coli. 

But how can something so small cause visible damage?

"It all comes down to velocity," said Vishnu Reddy, an astronomer at the University of Arizona. Objects at the altitude of the ISS and most other satellites — around 250 miles (400 kilometers) above Earth — revolve around our planet once every 90 minutes, according to the European Space Agency. That's more than 15,600 mph (25,200 km/h), 10 times the speed of an average bullet shot on Earth, Robert Frost, an instructor and flight controller at NASA, wrote on Quora. 

Related: What would happen if you shot a gun in space? 

The energy of an impact isn't just related to the size of an object; velocity (speed and direction) are equally important. That's why a small bullet can cause so much damage; when moving at a high enough velocity, any object could be dangerous, Reddy told Live Science. 

Keep in mind that velocity is additive, said Kerri Cahoy, an associate professor of aeronautics and astronautics at the Massachusetts Institute of Technology. So, if two objects are moving toward one another when they collide, that increases the energy of their impact. 

"Think of it like driving on a highway," Cahoy told Live Science. Two fast-moving cars moving in the same direction could touch and just "barely kiss one another," she said. But if a vehicle — even a lightweight one, like a motorcycle — hits a car while speeding in the opposite direction, it could be disastrous for both drivers. 

Likewise, in space, a fast-moving fleck of paint that collides with the ISS can leave a relatively big mark.

In space, satellites, spacecraft and debris orbit along many different paths; while one object might orbit horizontally around the equator, another might loop vertically around the poles. Some objects even move "in retrograde," meaning they rotate counter to the Earth’s orbit. As more and more debris clutters space, Earth's low orbit (in which the ISS rotates) turns into a packed highway at rush hour. "There can be the potential for a lot of damage," Cahoy told Live Science. 

The astronauts onboard the ISS were lucky that a larger piece of debris didn't hit their window. A microbe-size fragment may leave only a dent, but a pea-size fragment can disable critical flight systems, according to the European Space Agency. A piece of debris the size of a ping-pong ball? "That would be catastrophic," Reddy said. At that size, space junk could cause the space station to rapidly depressurize, making it impossible for astronauts to breathe onboard, Reddy said.

Space junk is a growing problem. Earth's orbit contains at least 128 million pieces of debris, and 34,000 of them are larger than about 4 inches (10 centimeters), according to the Natural History Museum in London — and those are just the fragments that are large enough to detect. These smaller pieces form when satellites naturally weather under extreme ultraviolet radiation, when larger pieces of space debris collide or when satellites are intentionally destroyed. Larger pieces include 3,000 derelict satellites, as well as bolts and other parts shed by spacecraft during launches.

By tracking space junk, scientists can tell countries and companies when to maneuver a spacecraft out of the path of a speeding piece of debris, Reddy said. The ISS has performed 25 of these maneuvers since 1999, according to the Natural History Museum. And researchers are developing ways to fish junk out of space, such as using hooks, nets and magnets to pull it back into Earth's atmosphere. 

Too much space junk could make it dangerous for humans to use Earth's orbit for satellites and other types of spacecraft. We're nowhere near that point now, but it's important to get ahead of the space junk problem to prevent further accumulation, Reddy said. 

"We rely on space for so many things: communication, forecasting weather, banking, entertainment and military," he said. "In terms of our progression as a civilization, we would go many steps backward if we did not have access to space."

Originally published on Live Science.

More than 100 miles (161 kilometers) of Israel's normally pristine Meditteranean coastline have been stained with thick globules of tar that washed up after an oil spill off the coast of the country last week. Authorities have yet to identify the culprit, but they say it is harmful to both humans and marine life.

Israel's Nature and Parks Authority (INPA) called the spill "one of the most serious ecological disasters" the country has ever seen and warned it could take years to completely remove the waste from beaches, according to the BBC.

The tar was first noticed on Israel's beaches on Wednesday (Feb. 18) after a heavy winter storm battered the coastline. Israel's Environmental Protection Ministry estimates that as much as 1,100 tons (1,000 metric tons) of tar have already washed ashore, according to Aljazeera.

Related: The 10 weirdest spills in nature

Normally, oil spills form a thin slick across the water surface, with some washing up on beaches in a more liquid form. The Israel spill, however, turned into tar balls because rough sea conditions  brokeup the slick and mixed it into the seawater for several days creating small concentrated blobs of congealed oil (tar balls), according to NOAA. 

On Saturday (Feb. 21), satellite images from the European Maritime Safety Agency showed that the spill had most likely originated about 31 miles (50 kilometers) off Israel's coast, but the exact cause of the spill and what is responsible for it are still unknown, according to Haaretz.

Thousands of volunteers turned out at beaches across Israel's coastline once the storm subsided to remove the tar by hand, after environmental NGOs including Ecoocean and Zalul requested the public’s help. Soldiers from the Israeli army were also sent to help deal with the cleanup effort.

However, several volunteers had to be taken to hospital after breathing in toxic fumes given off by the sludge. On Sunday (Feb. 22), government officials closed the entire length of Israel's 120-mile (195 km) Mediterranean coastline to members of the public, due to health concerns.

Marine life impacts 

Although it is still too early to know the exact impacts of this spill on the marine environment, officials fear that it could be extremely damaging, according to Aljazeera.

On Wednesday (Feb. 18), a 55-foot-long (17 meters) fin whale washed up dead on a beach in southern Israel at the same time as the first globules of tar were washing up to the north. A necropsy (animal autopsy) by INPA veterinarians revealed the whale's stomach was filled with a black liquid; further testing that's being undertaken will confirm whether that liquid is oil.

Several distressing photos have also circulated online showing juvenile turtles covered in black sludge that have washed up across the coastline. Some were taken to the Israeli Sea Turtle Rescue Center, but many were already dead when they washed up, Haaretz reported.

Whales, turtles and seabirds are some of the most at risk marine animals from oil spills because they breathe and feed at the surface.

"Imagine that you tar a roof to seal it. Imagine a whole world of living things being sealed off and suffocated by tar," said Ruth Yahel, a marine ecologist with INPA, talking to the Times of Israel.

And experts worry that the tar that has washed ashore is only a fraction of the toxic sludge still out there.

"The greatest fear is that there is a lot more tar in the sea right now that is poisoning wildlife, and still hasn't reached us," said Dor Adelist, a marine scientist from the University of Haifa, talking to the news outlet Walla, as reported by the Times of Israel.

Environmental controversy 

Environmental groups, including INPA, have criticized the government in the wake of the oil spill after multiple failed attempts to establish programs and funding to deal with oil spills in the last two decades, according to the Times of Israel. As a result, there were no real plans in place to effectively deal with the sticky situation when it began.

There is also some controversy about the origins of the spill.

The Environmental Protection Ministry (EPM) was investigating a number of ships believed to have been in the vicinity of the spill and therefore potentially responsible for the mess. "We are making every effort to find those responsible for the disaster, and we will bring to the government's approval tomorrow a proposal for resolutions to rehabilitate the environment," said EPM minister Gila Gamliel in a tweet, according to Aljazeera.

However, on Monday morning (Feb. 22), a judge had issued a gag order on details pertaining to the oil spill. This prevents the Israeli press from publishing anything about the identity of any suspects or vessels involved, including their cargo, destination and port, for a week. The Israeli news outlet Haaretz called the gag order an "unusual move" that could suggest some sort of cover-up.

The spill also coincides with the recent signing of an agreement to build a new oil pipeline between the United Arab Emirates (UAE) and Israel, which was announced in October 2020. Environmental groups have opposed the project and say this spill is only a taste of what is to come if there is a leak from a new pipeline.

Rachel Azaria, chair of Life and Environment — an umbrella organization representing 130 charities and NGOs — called the spill "a promo for a catastrophe that could be 250 times as bad," speaking to the Times of Israel.

Originally published on Live Science.

"Only we humans make waste that nature can't digest." Those are the words of oceanographer Capt. Charles Moore, who discovered the Great Pacific Garbage Patch in 1997. And, of course, he's talking about plastic.

Most people reading this will probably have something made of plastic within their line of sight. This material is ubiquitous: we're now producing more than 300 million tons (272 metric tons) of plastic a year, and roughly half of that is intended for single-use — meaning that it's discarded immediately after it has served its purpose. This has led to a mounting problem of plastic waste going to landfills, and some of this waste gets blown off course and makes its way into rivers and ultimately the sea. In fact, around 8 million tons (7.2 million metric tons) of plastic pollution enters the ocean every year, where it entangles marine life, pollutes coral reefs and ultimately — subjected to degradation by water, wind and sun — breaks apart into trillions of tiny microplastic pieces. 

These particles of plastic look a lot like food to many marine species, who then gorge on the pollution, and end up starving from lack of real nutrition. The surface of microplastics also attract pollutants in the ocean, and end up transporting these into the bodies of animals, with effects we're still trying to understand. There's a possibility that microplastics could be harming humans as well, because we consume them via seafood and even in drinking water: in 2019, the World Health Organization called for more research into the potential impacts of microplastic pollution on our health.

Related: How much plastic actually gets recycled?

Underpinning all this is the fact that, depending on the ingredients used to make it, plastic can be incredibly resilient and might never truly biodegrade (which for the purposes of this article, means being efficiently reduced to basic reusable compounds in nature, by the microorganisms in water and soil). Pair that with the volume of plastic pollution in our environment, and we have a clear problem. Most single-use plastics entering the ocean, for instance, will stay there for centuries. 

How did we create this crisis of persistent plastic? The answer lies in the process we use to make plastic itself. But first, it's important to understand that "plastic" isn't just the shopping bags we picture floating in the ocean. 

What is plastic?

"The term 'plastic' often covers a wide range of heterogeneous materials, each with differing applications that require very different physical properties," said Carl Redshaw, a chemist at the University of Hull in the United Kingdom and a participant in the university's Plastics Collaboratory project, which conducts research to improve the sustainability of the plastics industry. "In fact, more than 300 types of plastics are known," Redshaw told Live Science. 

So, if plastics are so different, what do they have in common? They're made of polymers, which are molecules comprising many repeating units, in formations that give plastics many of the desired qualities — such as flexibility, malleability and strength — that they often share. Beyond that, plastics generally fall into one of two broad categories: bio-based plastics, in which polymers are derived from sources such as cornstarch, vegetable fats and bacteria; and so-called 'synthetic' plastics, in which polymers are synthesized from crude oil and natural gas. 

Despite the Earth-friendly name, bio-based polymers don't automatically have a good environmental track record, because they may also persist in the environment and not biodegrade. "Not all bio-based plastics are biodegradable polymers, and not all biodegradable plastics are bio-based," Redshaw explained. Nevertheless, oil- and natural gas-derived materials comparably cause the starkest environmental harm, because plastics in this category tend to persist in the environment for longer — while causing other environmental impacts, too.

To understand why, we're going to look at an example of oil-derived plastic: take the milk bottle chilling in your fridge. This carton begins its life somewhere far more dramatic — deep in the bowels of the Earth, as crude oil. This substance, pooling in high-pressure chambers within the Earth's crust, is drilled and pumped to the surface and carried through pipelines to oil refineries. Its dense sludge is made up of hydrocarbons, compounds made from combinations of carbon and hydrogen atoms that form chains of varying lengths, giving them different properties. These hydrocarbons are the earliest raw materials of plastic, ready-made by the Earth. 

Related: If you throw a compostable cup in the trash, does it still break down?

At the refinery, plastic production is truly set in motion. Here, molasses-like crude oil is heated over a furnace that separates the hydrocarbons into different groups— based on the number of atoms they contain and their resulting molecular weight — and then feeds them into a nearby distillation tube. Inside this tube, the longer, typically heavier hydrocarbons sink to the bottom, while the shorter, lighter ones rise to the top. The result is that crude oil gets separated into several distinct groups of chemicals for use — such as petroleum, gasoline and paraffin  — each of which contains hydrocarbons of a similar weight and length. One of these groups is naphtha, a chemical that will become the primary feedstock for making plastic. 

Naphtha is like gold dust for plastic production, because two of the many hydrocarbons it contains are ethane and propene. These two compounds are crucial to the formation of the most commonly produced and ubiquitous plastic products on Earth, including the type used for that milk carton. But to be made into something that can actually be used to build plastic, ethane and propene have to be broken down from their raw hydrocarbon state into smaller units. 

There are different ways to do this. One method is to apply high heat and high pressure in a zero-oxygen environment. This process, called "steam cracking," breaks down the hydrocarbons into shorter molecules called monomers. 

"Monomers such as ethylene from ethane, or propylene from propene, can be derived straight from naphtha after thermal cracking," (which incorporates steam cracking), said Payal Baheti, a postdoctoral researcher at Aston University focusing on sustainable polymer materials. The simplified ethylene and propylene, finally, are the precious ingredients needed to make plastic's backbone. 

This next step unfolds through a process called polymerization, wherein those individual monomer ingredients are combined chemically in new arrangements to produce the long repeating chains known as polymers. In this case, ethylene and propylene form polyethylene and polypropylene — the two most common and widely produced polymers on Earth. 

So, why are these two polymers so popular? Polyethylene's makeup allows it to be used to make plastics of different densities — meaning it can be flimsy and pliable, or sturdy and tough — thus making its applications extremely diverse. Meanwhile, polypropylene's configuration makes it particularly flexible and resilient. Consequently, we see these types of plastic every day, predominantly in single-use items such as the milk carton, not to mention plastic wrappers, straws, water bottles, shopping bags, shampoo containers, bottle caps — the list goes on.

Related: What happens inside a landfill?

Yet, these are just two varieties of synthetic plastics out of many dozens more. Other types of hydrocarbons are isolated and broken down from different sources — not only from crude oil but also from natural gas — and are used to make plastic, too. In some cases, polymers might be made of a single monomer, repeated, as we see in polyethylene and polypropylene, or they might involve combinations of a few types of monomers. 

What's more, each of those polymer chains will then be processed in a variety of ways and mixed with various additives — antioxidants, foaming agents, plasticizers, flame retardants — that equip them to fulfill the variety of niche functions that make plastics so versatile. 

"Different plastics need to have different properties," Baheti told Live Science. "Take the example of food packaging, which should deter the passage of excess oxygen or sunlight, to avoid degradation, so it contains additives to make it so. "One could say it's the additives that give a polymer its properties and leads to the formation of a plastic." 

These final flourishes create the huge diversity of plastic products we have today — and that make enormous contributions to food production and storage, cosmetics, technology, medicine and health care.

"Alien material"

Now, let's fast-forward through that production process once more. Plastic that's synthesized from oil and natural gas is made by isolating hydrocarbons, breaking them down into their component parts and then reconstituting these parts into entirely new formations never before seen in nature. Simply speaking, this creates an "alien" material unfamiliar to microbes in Earth's water and soil, Baheti explained. "The carbon backbone found in synthesized plastic is not recognized by soil's bacteria, meaning they cannot digest and convert it into water and carbon dioxide." 

"The likes of polyethylene can take centuries to decompose in landfill sites," Redshaw said. "This means much of what has been produced during our lifetime still remains in its near original form. And persistence isn't the only issue: as it gradually breaks apart under the influence of sunshine, water and  wind, oil- and natural gas-derived plastic releases greenhouse gas emissions contained within, as well as leaching the chemicals added during production back into the environment. The sheer volume of single-use plastic pollution, especially — combined with its persistence and an ongoing environmental impact that can last for centuries — has created the environmental catastrophe we see today. 

Related: How much trash is on Mount Everest?

But there may be a way out of this mounting pile of trash. Redshaw believes biodegradable plastics — which are a focus of his research — could be one potential solution. To rehash, making biodegradable plastic doesn't necessarily mean producing it from bio-based sources like corn starch (although that could provide a solution). More specifically, it entails making plastic from polymers that can be broken down reasonably efficiently by microbes in water and soil. 

For this to have real planetary impact, biodegradable polymers would need to replace the likes of oil-based polyethylene and polypropylene — but while also maintaining properties like strength and flexibility that make these conventional polymers so desirable. That's a tall order, made trickier by the fact that conventional polymers remain competitively cheaper to make. 

But a few biodegradable options are starting to make headway. One is a type called polylactides, which are being used to make single-use items such as cups, cutlery and straws, that could biodegrade more effectively once they're in the environment. These kinds of inventions are likely to increase as global pressure grows to make plastic more sustainable, Redshaw reckoned.

There are hints of optimism elsewhere, too. In 2016, researchers discovered plastic-eating bacteria, and others have since identified polyethylene-munching worms (this beastie is a caterpillar of the greater wax moth, Live Science previously reported). They've also found enzymes that can be engineered to break down plastic waste. 

"Maybe, in the years ahead, we will learn from the bacteria and worms that possess the ability to break down and digest plastics, even stuff like polyethylene carrier bags, and design large, artificial worms that can eat their way through our plastic waste — like the giant maggots that featured in 'Doctor Who' back in the '70s!" Redshaw said. 

In any case, in the process of creating plastic, humans have managed to take raw materials from nature and transform them so thoroughly that nature no longer recognizes them. Our ingenuity is what got us in this mess; now, hopefully, it can get us out.

Originally published on Live Science.

The war against plastic may be overshadowing greater threats to the environment. In a collaboration with experts from the environmental sciences, engineering, industry, policy and charities, we have written a paper in the journal WIREs Water which highlights concerns that relatively easy action against plastic pollution can conveniently mask environmental apathy, and that people are being misled by alarmist headlines, emotive photographs, and "greenwashing."

Plastic is an incredibly useful and versatile material on which much of modern society relies, yet it has become one of the most topical environmental issues of the day. Over the past few years, plastic pollution has encouraged action from individuals, organizations and governments at levels similar to some of the greatest threats to the environment, such as climate change and biodiversity loss.

This concern is well founded. Plastic pollution is unsightly, can entangle wildlife, can be ingested and block stomachs and intestines, and may carry harmful chemicals. It can break down into small pieces, eventually to microplastics – pieces smaller than 5 mm – that can accumulate up the food chain. It has also been found in some of the most remote parts of the world.

But though there is widespread animosity towards plastics, they are a group of materials that we cannot live without, and that we should not live without. We argue that plastics themselves are not the cause of the problem, and that failing to recognize this risks exacerbating much greater environmental and social catastrophes.

Some pollution is less visible

The environmental impacts of some less visible pollutants are well known. Greenhouse gasses such as carbon dioxide and methane contribute to global warming. Fine particles in the atmosphere are associated with respiratory illnesses and are a major component of smog. And radiation from the Chernobyl nuclear disaster continues to impact the wildlife that has taken over its exclusion zone.

But society pollutes the environment in more ways than most people are aware, and has done since long before concern for plastic pollution became prevalent. Agriculture leads to nutrient over-enrichment and pesticide pollution. Electronics, vehicles and buildings require a wide variety of toxic metals that leak into the environment at the end of their lives and are blown and washed from where they are mined. Medicines that are washed down drains and not completely metabolised (used up) by our bodies can also find their way into rivers and lakes.

These lesser known realities of everyday consumption degrade the environment and are toxic to wildlife. As chemicals, rather than particles like plastic, these pollutants are also far more mobile than plastics and, in the case of toxic metals, more persistent.

Plastic pollution provides a convenient distraction from these inconvenient truths. Starting with political legislation at the very top, high-profile action against plastic pollution has been disproportionate to its environmental impact.

Banning microbeads in cosmetics, for example, addressed only a very small part of the problem. This is not to say that microbeads are not present in the environment or that they do not pose a risk to it. But those who are in positions of power – scientists, industry, the media, politicians – have an obligation not to mislead their audiences by disseminating research and environmental policy that lacks context.

Focus on the product – not the plastic

Plastic is just one type of anthropogenic material in the environment. Plastic textile fibres such as polyester or nylon are a prominent form of pollution, but it is natural fibres like wool and cotton that have recently been found to dominate environmental samples. Though biodegradable, when these natural fibres do degrade they may leach harmful chemicals, such as dyes into the environment.

Glass and aluminium, sometimes promoted as solutions to plastic bottle pollution, can have greater carbon footprints than the plastics they replace. And many of these alternatives will also persist in the environment. Someone who will throw a plastic bottle into a river will not change their behaviour if they have an aluminium can.

The problem is the product, not the plastic. A desire for convenience, industries reliant on overconsumption not informed consumption, and a culture of policies for popularity not progression, are all at the root of the plastic conversation. But the plastic pollution is just the bit you can see.

So what should we do?

"Plastic" and "plastic pollution" are all too often confused. Plastic pollution is a visible and easily relatable symptom of unsustainable levels of consumption, inappropriate product design, poor waste management and disingenuous policy.

Greenhouse gas emissions, biodiversity losses, exploitative labor practices and chemical pollution either cannot be seen so clearly or their effects develop over a longer period of time. But once their impacts are visible, it is often too late for the environments they afflict. That’s why there is a pressing need to raise the profile of the pollution that cannot be seen.

Plastic pollution has mobilized unprecedented levels of environmental action. But to be successful this action needs to focus on the true causes, like the overconsumption of readily disposable items, rather than simply the presence of plastic in the environment. It should also do a better job of framing plastic pollution within the context of other, more significant pollutants.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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An estimated 15 million tons (14 million metric tons) of microplastics have settled in the deep ocean, according to a new report by Australia's national science agency. That's more than double the amount of plastic pollution at the ocean's surface. 

Researchers sampled seafloor sediments in locations hundreds of miles from Australia's coastline, discovering that the quantity of microplastics was far higher than anticipated. 

From that evidence, they calculated how widespread microplastics might be in ocean sediments worldwide — and their staggering number was a conservative estimate, they wrote in the report.

Related: Images of the Great Pacific Garbage Patch

Prior studies have shown that millions of tons of plastic enter the ocean each year. And though scientists recognize plastic pollution as an important ecological issue, little is known about plastic accumulation near the sea bottom and what its impacts might be on marine life and ecosystems. This is especially true of microplastics; plastic particles that are less than 0.2 inches (5 millimeters) in length, no bigger than a sesame seed, according to the National Ocean Service.

"The extent of microplastic pollution in deep-sea sediments has historically been poorly known," said study co-author Denise Hardesty, a principal research scientist with Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), a government agency responsible for scientific research. 

"That's understandable given how difficult, time-consuming and costly it is to sample the depths of the 'big blue'. But understanding how much microplastic finds its way to the seafloor is imperative for predicting the distribution and potential impacts of global plastic pollution," Hardesty told Live Science in an email.

Separated from sediment

For the new study, the scientists used remotely operated vehicles (ROVs) to scoop 51 seafloor cores — cylinders of packed sediment — from six locations in an ocean region off the coast of southern Australia, known as the Great Australian Bight (a "bight" is a curve in a coastline holding an open bay). They sampled at depths ranging from 5,430 to 10,046 feet (1,655 to 3,062 meters), at distances of 179 to 221 miles (288 to 356 kilometers) from the shore.

Rinsing the samples and spinning them in a centrifuge flushed away organic matter, making the microplastics easier to detect. The researchers then stained the samples with fluorescent dyes, isolating and identifying microplastic particles with an optical microscope that used fluorescence to highlight organic material, according to the study.

In the samples, a single gram of seafloor sediment held as many as 14 plastic particles. Based on the average number of particles in the samples and the size of the ocean — which covers 139.4 million square miles, or 361.1 million square km — the scientists calculated that the total, global amount of microplastics on the seafloor would be between 9 million and 15 million tons (8 million and 14 million metric tons). 

However, the amount of ocean microplastics worldwide could easily be much higher, Hardesty told Live Science. Particle density from the Great Australian Bight was likely lower than in ocean regions that are nearer to heavily populated coastal areas. And plastic microfibers, another known source of microplastic ocean pollution, were omitted from the analysis, in case the fibers they found in the sediment cores were introduced by clothing or other fabrics after the samples were collected.

"We didn't expect to have such high recorded levels of microplastics, particularly given how careful our sampling approach was," Hardesty said. "Therefore, our results are a conservative estimate of how much microplastic there is in deep-sea sediments."

The impacts of larger plastic pollution on ocean life and ecosystem health are all too clear, visible in great garbage patches that collect at the sea surface; as hardened "plasitcrusts" coating island coastlines; as deadly nooses that strangle sharks and rays; and as obstructions that fill the bellies of dead sea turtles and whales. 

"These findings highlight the extent of plastic pollution, and shows that no area of the ocean is immune to the plastic problem. We hope this work has people thinking about the choices we make, the impacts of what we make, buy, use and discard and where it can end up," Hardesty said. 

"Hopefully, people start to see the connection between what we do in our daily lives and how far-reaching those impacts may be on what are considered the most pristine ecosystems in the world," she said.

The findings were published online Oct. 6 in the journal Frontiers in Marine Science.

Originally published on Live Science.

Thousands of dead octopuses, starfish and other sea creatures have recently washed up on the shores of the remote Russian peninsula of Kamchatka. The normally pristine waters surrounding Kamchatka have become discolored and developed an odd smell, say locals. Surfers say the water is mildly burning their eyes. 

It turns out an unidentified pollution event may have spilled a slew of toxic chemicals into the water, according to recent news reports. 

After reports from surfers and locals surfaced, divers confirmed a widespread mass die-off, and Greenpeace Russia called it an "ecological disaster," according to The Guardian. Widely circulated photos and videos of the dead creatures sparked outcry from the public and speculation from local news outlets as to what could have caused it, CBS News reported. 

Related: 8 ways that air pollution can harm your health

The pollution seems to have badly hit the sea creatures that live at the bottom of the seafloor, wiping out as many as 95% of them in Kamchatka's Avacha Bay, Ivan Usatov, a researcher at the Kronotsky Reserve and the Pacific Institute of Geography Kamchatka Gov. Vladimir Solodov, according to the Kamchatka government website. Usatov and other researchers studied the area around Avacha Bay by taking samples and diving to the sea-floor. "Some large fish, shrimps, crabs have survived, but in very small numbers," Usatov said. But "the condition of marine mammals and birds is normal. On the shore, we also did not find any emissions of large dead sea animals, birds." 

It's likely that this event severely disrupted the food chain as the animals that feed on those bottom-dwelling creatures will also die, the researchers said.

Last week, officials blamed the scores of dead animals on stormy weather. But a recent analysis of water samples revealed that it was contaminated with a number of potentially dangerous substances. The samples contained petroleum products, some of which were at levels that were four times above normal, Aleksei Kumarkov, the region's acting Minister of Natural Resources and Ecology said, according to CBS News.

The water also had more than twice the expected levels of compounds called phenols, which can cause irritation to the skin, eyes, nose, throat and nervous system, according to the Centers for Disease Control and Prevention (CDC). At high enough doses, phenols can cause liver or kidney damage, skin burns, tremors, convulsions and twitching, according to the CDC.

There are "no grounds to talk about any specific version" of what might have killed all of these animals, Solodov told reporters at a news conference on Monday (Oct. 5), according to CBS News.

Solodov posted on Instagram that he would lead a "transparent" investigation into the issue and fire any official who tries to cover up the scale of the pollution. As part of this investigation, he said there would be investigations on Tuesday (Oct. 6) at two military testing sites, Radygino and Kozelsky, both near a local river with "yellow film" on it, according to The Guardian.

The containers holding old rocket fuel stored in Radygino, about 6 miles (10 kilometers) from the sea, could have rusted, leaking fuel into the water, Vladimir Burkanov, a biologist said in Russia’s opposition newspaper Novaya Gazeta, according to The Guardian. Kozelsky, where toxic chemicals and pesticides are buried,  could have also had a leak, according to The Guardian. Multiple different groups are continuing to investigate the incident.

Originally published on Live Science.

Glyphosate is a chemical compound that works as an effective herbicide, or weed killer. It's the most commonly used herbicide chemical in the world, according to a 2016 study in the journal Environmental Sciences Europe. Glyphosate may be sprayed anywhere there are unwanted plants — from commercial farms to private backyards. 

Who invented glyphosate?

Henri Martin, a Swiss chemist, was the first to synthesize glyphosate while trying to develop new pharmaceuticals in 1950, according to a review in the journal Pest Management Science. But the chemical didn't have much use in the pharmaceutical world. 

Twenty years later, John E Franz, a chemist at the agrochemical company Monsanto, independently synthesized glyphosate after his colleagues found that chemicals similar to glyphosate were slightly harmful to plants. Franz found that glyphosate was a highly efficient plant-killer. Monsanto promptly patented the chemical and began selling its glyphosate herbicide under the trade name Roundup in 1974.

Roundup took off in popularity when Monsanto began to sell "Roundup-ready" crops in 1996. These plants, which included soybeans and corn, are genetically modified to survive being sprayed with Roundup. Between 1995 and 2014, global glyphosate use grew 12-fold, according to the 2016 study published in Environmental Sciences Europe.

Monsanto's patent on glyphosate expired in 2000, making the product available for other companies to sell. Today, there are hundreds of glyphosate herbicides on the market.

What is glyphosate used for? And how does it work?

Glyphosate is most commonly used in agriculture, the Environmental Sciences Europe study found. Farmers use the practical herbicide to kill weeds that compete with crops for sunlight, water and soil nutrients. Glyphosate has been used more than any other agriculture chemical, with an estimated 8.6 billion kilograms (19 billion lbs.) of it sprayed since 1974 to help grow everything from peppers to oranges. 

When the chemical is sprayed onto a plant, it usually seeps into the plant via the leaves, said Ramdas Kanissery, a weed scientist at the University of Florida in Immokalee, Florida. From there, glyphosate can travel from cell to cell and spread to the stem and the roots, infecting the entire plant. 

Glyphosate is derived from an amino acid called glycine and plant cells treat glyphosate as though it were amino acid. Plants use amino acids to build things like enzymes and proteins that it needs in order to grow, through a process called amino acid synthesis. "But once glyphosate ends up in [the plant's] amino acid synthesis cycle, it will mess up everything," Kanissery said. That's because glyphosate interferes with a crucial enzyme production pathway that prevents the plant from creating necessary proteins, and within two to three weeks of glyphosate exposure, the plant will die.

People also use glyphosate at home to tame weeds, and some cities spray the chemical in their parks and other green spaces to control invasive plants that can take over and push out native plants. However, many local governments, such as the city of Seattle, Washington, have ended this practice as people have become increasingly concerned about the chemical's safety.

Related: This towering plant is invading the US, and it's causing serious sunburns

Why are people concerned about glyphosate?

Although glyphosate has cut farmers' costs and helped landscapers remove invasive plants, people have grown increasingly skeptical about whether the benefits outweigh the risks to human and environmental health. Recent research has shown that the chemical may be harming the wrong plants, in addition to wildlife and people.

Even if glyphosate is targeted at a specific plant, it can end up in unexpected places. "Glyphosate is a non-selective herbicide," Kanissery explained. That means that it can hurt any plant it reaches, even native plants that it's used to protect. 

Someone spraying it on weeds may accidentally aim some toward their grass, for example. And when farmers spray it on their field on a hot and humid day, aerosolized droplets of the liquid herbicide can move through the air like a cloud and may eventually fall on neighboring fields, in a process called drift, according to the U.S. Environmental Protection Agency (EPA). 

And no matter how carefully someone sprays it, a large portion of the liquid solution will wind up in the soil below, Kanissery said, where it can travel into the roots of non-targeted plants and kill them. Glyphosate can persist in soil for months before microorganisms in the ground eat it and recycle it into carbon dioxide.

Glyphosate is sold for its unmatched ability to harm plants, but researchers have found that the powerful herbicide harms animals, too. 

For example, a 2018 study published in the journal Proceedings of the National Academy of Sciences found that the chemical could alter the microbe communities in some bees' guts, making the bees more susceptible to infection. And a 2018 study published in the journal PLOS ONE showed that honeybees exposed to glyphosate had smaller and more developmentally delayed larvae. Other studies have shown that glyphosate exposure can disrupt bees' sleep and navigation. 

Nonetheless, Bayer (the company which bought Monsanto in 2018) claims that glyphosate is safe for bees. Their claim is supported by limited research, including a 2015 study from the United States Department of Agriculture that simulated the way bees would be sprayed with glyphosate on a field and concluded that the chemical didn't hurt the bees.

Glyphosate has also made headlines for its suspected link to a class of cancers called non-Hodgkin lymphoma (NHL). The link has been debated in courtrooms and continues to be tested by scientists. In 2015, the World Health Organization (WHO) called the chemical "probably carcinogenic to humans," based on animal studies, which constituted the best evidence at the time. But the U.S. EPA maintains that glyphosate is "unlikely to be a human carcinogen," based on several studies, including a large study of agriculture workers published in 2017 in the Journal of the National Cancer Institute, which found no link between glyphosate and cancer.

A 2019 review published by independent researchers in the journal Mutation Research/Reviews in Mutation Research examined data from several studies on glyphosate's potential carcinogenic effects, including a large sample of farmworkers in the United States. The review found that workers exposed to the highest amounts of glyphosate herbicides had a 41% greater risk of developing NHL.

"I'm convinced that [this number] is still an underestimate," said the study's lead author Luoping Zhang, a toxicologist at the University of California, Berkeley. The data the researchers analyzed was collected through 2010, Zhang said, but glyphosate use has increased since then. Plus, many years could pass between a person's exposure to the chemical and resulting cancer, she said.

Additional studies on the health effects of glyphosate exposure have supported what Zhang and her colleagues discovered in their 2019 review. For example, a separate 2019 study published in the International Journal of Epidemiology pooled data on glyphosate exposure and the health of farmworkers in the U.S., France and Norway, and similarly found that exposure to the chemical was associated with some types of NHL.

Still, research on the subject remains sparse. Scientists would need to conduct many more studies with human subjects and get similar results before glyphosate could be definitively linked to NHL or any other cancer.

And key questions remain unanswered. For example, scientists don't yet have a handle on how, exactly, the chemical could trigger cancer to develop. And they don't know how much exposure to the chemical is needed to pose a risk.

It's unlikely that the amount of glyphosate that makes its way into food is enough to cause cancer, according to the WHO. Those at greatest risk are farmworkers who could be inhaling the chemical and absorbing relatively large amounts of it through their skin and eyes when they spray it, Zhang said. Some researchers suspect other diseases may also be linked to glyphosate exposure, such as celiac disease, Zhang added, but there's very little evidence to support this.

What are people doing about it?

After the WHO called glyphosate "probably carcinogenic to humans" in 2016, people with NHL started filing lawsuits against Monsanto, and later Bayer, attributing their cancer to Roundup. Tens of thousands of people have since filed lawsuits against Bayer over Roundup, according to the company.

The first Roundup cancer case to make it to trial was brought by a California school district groundskeeper named Dewayne Johnson in 2018. Johnson was awarded $289 million in damages and the award was reduced to $20.4 million through appeals, according to Baum Hedlund Law, the law office that represented Johnson.  

Two more similar cases were filed against Bayer in 2019. Edwin Hardeman developed NHL after he sprayed Roundup on his property for decades. He was awarded $80 million, which was later reduced to $25.2 million. The third case to go before a jury was brought by a couple, Alva and Alberta Pilliod, who began using Roundup in the 1970s. They were awarded more than $2 billion, which was reduced to $87 million. The plaintiffs in both cases were also represented by Baum Hedlund Law. 

In June 2020, Bayer agreed to pay more than $10 billion to settle nearly all of the 125,000 cases currently filed or expected to be filed against them. The settlement does not include those of Johnson, Hardeman or the Pilliods, all of which are in the appeals process. In settling, the company hopes to prevent years of costly litigation and "return the conversation about the safety and utility of glyphosate-based herbicides to the scientific and regulatory arena and to the full body of science," said Bayer CEO Werner Baumann in a press release.

Additional resources: 

• Find answers to frequently asked questions about glyphosate from the U.S. FDA.
• Here are a few general facts about glyphosate, from the National Pesticide Information Center. 
• Read more about the debate over the safety of glyphosate, from Frontiers in Public Health.

Editor's note: This article was updated on Sept. 21, 2020 to correctly state the final amount Dewayne Johnson was awarded in his lawsuit against Monsanto/Bayer.