Tiny plastic particles in the environment

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trader32176
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Tiny plastic particles in the environment

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Tiny plastic particles in the environment

5/4/21


https://phys.org/news/2021-05-tiny-plas ... nment.html


Wherever scientists look, they can spot them: whether in remote mountain lakes, in Arctic sea ice, in the deep-ocean floor or in air samples, even in edible fish—thousands upon thousands of microscopic plastic particles in the micro to millimeter range. This microplastic is now even considered one of the defining features of the Anthropocene, the age of the Earth shaped by modern humans.

Microplastics are formed by weathering and physicochemical or biological degradation processes from macroscopic plastic products, such as the tons of plastic waste in the oceans. It is unlikely that these degradation processes will stop at the micrometer scale. And so there is growing concern about the potential harmful effects nanoplastics could have on various ecosystems. "Numerous media reports suggest, through their sometimes highly emotional coverage, that we are facing a huge problem here," says Empa researcher Bernd Nowack, who has long studied the material flows of synthetic micro- and nanoparticles, for example from textiles or tire abrasion, into the environment. But Nowack says at present this statement can hardly be substantiated by scientific findings: "We don't even know how much nanoplastics there is in the different ecosystems."

Huge gaps in knowledge

This is primarily because it is enormously difficult in terms of measurement technology to identify artificial nanoparticles made of plastic in environmental samples with thousands and thousands of (natural) particles of similar size. Appropriate analytical methods would first have to be developed, says Denise Mitrano of ETH Zurich. And then it would be a matter of understanding exactly what risk the tiny plastic particles—some of which differ considerably in their chemical composition—pose to humans and the environment, in other words: how dangerous they ultimately are. Adds Nowack, "So we can't justifiably say we have a serious problem here—but we also can't say we don't."

That's because the smaller particles become, the more likely they are to reach organs and tissues that are inaccessible to larger particles. The blood-brain barrier or placenta, for instance, prevents particles and macromolecules from passing through until they reach a certain size—or rather, smallness—thereby protecting the tissues and organs "behind" them, i.e. the brain and fetus, respectively, from potentially dangerous substances such as viruses and bacteria. "Even if we ingest microplastics, for example through our food, they probably do not enter our bloodstream or our brain, but are simply excreted again," says Peter Wick, head of Empa's Particles-Biology Interactions lab, who studies the interactions of nanoparticles with biological systems. "With nanoplastics, we can't be so sure."

Great need for research


Because of the enormous gaps in current knowledge, research into nanoplastics must thus be intensified, conclude Mitrano, Wick and Nowack. However, this should be done as systematically and broadly as possible—and with a cool head. After all, emerging pollutants do not always turn out to be as dangerous as originally assumed. "Our society initially adopts a zero-risk attitude toward many things that are new and unknown," Wick says. And that's understandable, he adds, especially in the case of nanoplastics, because, after all, "who wants plastic in their food?"

The solution to the problem, however, is as simple (at least in theory) as it is complex. On the one hand, a large proportion of nanoplastic particles are produced by the degradation of macro- and microplastics. Less plastic in the environment, therefore, reduces the amount of nanoplastics, and here every one of us can help stop polluting the environment with plastic waste. On the other hand, nanoplastics can also be created during the use of plastic products—for example, through abrasion—without the user being able to do anything about it. Indeed, our society is hardly possible without plastic. "The various polymers simply have too many positive properties for that," says Bernd Nowack.

More information: Denise M. Mitrano et al, Placing nanoplastics in the context of global plastic pollution, Nature Nanotechnology (2021). DOI: 10.1038/s41565-021-00888-2
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Re: Tiny plastic particles in the environment

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Microplastics found in Europe's largest ice cap

5/4/21


https://www.eurekalert.org/pub_releases ... 050321.php


In a recent article in Sustainability, scientists from Reykjavik University (RU), the University of Gothenburg, and the Icelandic Meteorological Office describe their finding of microplastic in a remote and pristine area of Vatnajokull glacier in Iceland, Europe's largest ice cap. Microplastics may affect the melting and rheological behaviour of glaciers, thus influencing the future meltwater contribution to the oceans and rising sea levels.

This is the first time that the finding of microplastic in the Vatnajökull glacier is described. The group visualised and identified microplastic particles of various sizes and materials by optical microscopy and μ-Raman spectroscopy.

The discussion about microplastics has mainly been focused on the contamination of the sea, but hitherto little research has been conducted on plastic in the earth's ice caps. To date, microplastic particles have been found in the Italian Alps, in the Ecuadorian Andes and icebergs at Svalbard. According to Dr Hlynur Stefansson, Associate Professor at the RU Department of Engineering and first author of the article, understanding the distribution of microplastic and its short and long-term effects on the dynamics of ice is of vital importance.

The findings confirm that microplastic particles are distributed through the atmosphere. "We do not understand well enough the pathways for microplastic particles in our environment. Is the plastic carried by snow and rain? We need to know more about the causes. The samples we took are from a very remote and pristine location in Vatnajokull glacier, with no easy access, so direct pollution from human activity is unlikely," Dr Stefansson says. "We also need to know much more about the short and long-term effects of microplastic on the dynamics of the ice and if they contribute to the melting of glaciers. If that is the case, it will play a critical role in future meltwater contribution to the oceans and rising sea levels. The plastic particles degrade very slowly in the cold glacier environment and can accumulate and persist in the glaciers for a very long time. Eventually, however, they will be released from the ice, contributing to pollution in rivers and the marine environment. It is therefore very important to map and understand the presence and dispersal of microplastics in glaciers on a global scale."

###

Microplastics in Glaciers:
First Results from the Vatnajökull Ice Cap https://www.mdpi.com/2071-1050/13/8/4183/htm
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Re: Tiny plastic particles in the environment

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Microplastics are everywhere — but are they harmful?

Scientists are rushing to study the tiny plastic specks that are in marine animals — and in us.

5/4/21

https://www.nature.com/articles/d41586-021-01143-3


Dunzhu Li used to microwave his lunch each day in a plastic container. But Li, an environmental engineer, stopped when he and his colleagues made a disturbing discovery: plastic food containers shed huge numbers of tiny specks — called microplastics — into hot water. “We were shocked,” Li says. Kettles and baby bottles also shed microplastics, Li and other researchers, at Trinity College Dublin, reported last October1. If parents prepare baby formula by shaking it up in hot water inside a plastic bottle, their infant might end up swallowing more than one million microplastic particles each day, the team calculated.

What Li and other researchers don’t yet know is whether this is dangerous. Everyone eats and inhales sand and dust, and it’s not clear if an extra diet of plastic specks will harm us. “Most of what you ingest is going to pass straight through your gut and out the other end,” says Tamara Galloway, an ecotoxicologist at the University of Exeter, UK. “I think it is fair to say the potential risk might be high,” says Li, choosing his words carefully.

Researchers have been worried about the potential harms of microplastics for almost 20 years — although most studies have focused on the risks to marine life. Richard Thompson, a marine ecologist at the University of Plymouth, UK, coined the term in 2004 to describe plastic particles smaller than 5 millimetres across, after his team found them on British beaches. Scientists have since seen microplastics everywhere they have looked: in deep oceans; in Arctic snow and Antarctic ice; in shellfish, table salt, drinking water and beer; and drifting in the air or falling with rain over mountains and cities. These tiny pieces could take decades or more to degrade fully. “It’s almost certain that there is a level of exposure in just about all species,” says Galloway.

The earliest investigations of microplastics focused on microbeads found in personal-care products, and pellets of virgin plastic that can escape before they are moulded into objects, as well as on fragments that slowly erode from discarded bottles and other large debris. All these wash into rivers and oceans: in 2015, oceanographers estimated there were between 15 trillion and 51 trillion microplastic particles floating in surface waters worldwide. Other sources of microplastic have since been identified: plastic specks shear off from car tyres on roads and synthetic microfibres shed from clothing, for instance. The particles blow around between sea and land, so people might be inhaling or eating plastic from any source.

From limited surveys of microplastics in the air, water, salt and seafood, children and adults might ingest anywhere from dozens to more than 100,000 microplastic specks each day, Albert Koelmans, an environmental scientist at Wageningen University in the Netherlands, reported this March2. He and his colleagues think that in the worst cases, people might be ingesting around the mass of a credit card’s worth of microplastic a year.

Regulators are taking the first step towards quantifying the risk to people’s health — measuring exposure. This July, the California State Water Resources Control Board, a branch of the state’s environmental protection agency, will become the world’s first regulatory authority to announce standard methods for quantifying microplastic concentrations in drinking water, with the aim of monitoring water over the next four years and publicly reporting the results.

Evaluating the effects of tiny specks of plastic on people or animals is the other half of the puzzle. This is easier said than done. More than 100 laboratory studies have exposed animals, mostly aquatic organisms, to microplastics. But their findings — that exposure might lead some organisms to reproduce less effectively or suffer physical damage — are hard to interpret because microplastics span many shapes, sizes and chemical compositions, and many of the studies used materials that were quite unlike those found in the environment.

The tiniest specks, called nanoplastics — smaller than 1 micrometre — worry researchers most of all (see ‘Microplastics to scale’). Some might be able to enter cells, potentially disrupting cellular activity. But most of these particles are too small for scientists even to see; they were not counted in Koelmans’ diet estimates, for instance, and California will not try to monitor them.

One thing is clear: the problem will only grow. Almost 400 million tonnes of plastics are produced each year, a mass projected to more than double by 2050. Even if all plastic production were magically stopped tomorrow, existing plastics in landfills and the environment — a mass estimated at around 5 billion tonnes — would continue degrading into tiny fragments that are impossible to collect or clean up, constantly raising microplastic levels. Koelmans calls this a “plastic time bomb”.

“If you ask me about risks, I am not that frightened today,” he says. “But I am a bit concerned about the future if we do nothing.”

Modes of harm

Researchers have several theories about how plastic specks might be harmful. If they’re small enough to enter cells or tissues, they might irritate just by being a foreign presence — as with the long, thin fibres of asbestos, which can inflame lung tissue and lead to cancer. There’s a potential parallel with air pollution: sooty specks from power plants, vehicle exhausts and forest fires called PM10 and PM2.5 — particulate matter measuring 10 µm and 2.5 µm across — are known to deposit in the airways and lungs, and high concentrations can damage respiratory systems. Still, PM10 levels are thousands of times higher than the concentrations at which microplastics have been found in air, Koelmans notes.

The larger microplastics are more likely to exert negative effects, if any, through chemical toxicity. Manufacturers add compounds such as plasticizers, stabilizers and pigments to plastics, and many of these substances are hazardous — for example, interfering with endocrine (hormonal) systems. But whether ingesting microplastics significantly raises our exposure to these chemicals depends on how quickly they move out of the plastic specks and how fast the specks travel through our bodies — factors that researchers are only beginning to study.

Another idea is that microplastics in the environment might attract chemical pollutants and then deliver them into animals that eat the contaminated specks. But animals ingest pollutants from food and water anyway, and it’s even possible that plastic specks, if largely uncontaminated when swallowed, could help to remove pollutants from animal guts. Researchers still can’t agree on whether pollutant-carrying microplastics are a significant problem, says Jennifer Lynch, a marine biologist affiliated with the US National Institute of Standards and Technology in Gaithersburg, Maryland.

Perhaps the simplest mode of harm — when it comes to marine organisms, at least — might be that organisms swallow plastic specks of no nutritional value, and don’t eat enough food to survive. Lynch, who also leads the Center for Marine Debris Research at Hawaii Pacific University in Honolulu, has autopsied sea turtles that are found dead on beaches, looking at plastics in their guts and chemicals in their tissues. In 2020, her team completed a set of analyses for 9 hawksbill turtle hatchlings, under 3 weeks old. One hatchling, only 9 centimetres long, had 42 pieces of plastic in its gastrointestinal tract. Most were microplastics.

“We don’t believe any of them died specifically from plastics,” Lynch says. But she wonders whether the hatchlings might have struggled to grow as fast as they need to. “It’s a very tough stage of life for those little guys.”

Marine studies

Researchers have done the most work on microplastic risks to marine organisms. Zooplankton, for instance, among the smallest marine organisms, grow more slowly and reproduce less successfully in the presence of microplastics, says Penelope Lindeque, a marine biologist at the Plymouth Marine Laboratory, UK: the animals’ eggs are smaller and less likely to hatch. Her experiments show that the reproduction problems stem from the zooplankton not eating enough food3.

But, because ecotoxicologists started running experiments before they knew what kinds of microplastics exist in aquatic environments, they depended heavily on manufactured materials, typically using polystyrene spheres of smaller sizes and at concentrations much higher than surveys found .

Scientists have started shifting to more environmentally realistic conditions and using fibres or fragments of plastics, rather than spheres. Some have started coating their test materials in chemicals that mimic biofilms, which appear to make animals more likely to eat microplastics.

Fibres seem to be a particular problem. Compared with spheres, fibres take longer to pass through zooplankton, Lindeque says. In 2017, Australian researchers reported that zooplankton exposed to microplastic fibres produced half the usual number of larvae and that the resulting adults were smaller. The fibres were not ingested, but the researchers saw that they interfered with swimming, and identified deformations in the organisms’ bodies4. Another study5 in 2019 found that adult Pacific mole crabs (Emerita analoga) exposed to fibres lived shorter lives.

Most laboratory studies expose organisms to one type of microplastic, of a specific size, polymer and shape. In the natural environment, organisms are exposed to a mixture, says Koelmans. In 2019, he and his doctoral student Merel Kooi plotted the abundances of microplastics reported from 11 surveys of oceans, rivers and sediment, to build models of mixtures in aquatic environments.

Last year, the two teamed up with colleagues to use this model in computer simulations that predict how often fish would encounter microplastics small enough to eat, and the likelihood of eating enough specks to affect growth. The researchers found that at current microplastic pollution levels, fish run that risk at 1.5% of locations checked for microplastics6. But there are likely to be hotspots where the risks would be higher, says Koelmans. One possibility is the deep sea: once there, and often buried in sediment, it is unlikely the microplastics will travel elsewhere and there is no way to clean them up.

The oceans already face many stressors, which makes Lindeque more afraid that microplastics will further deplete zooplankton populations than that they will transfer up the food chain to reach people. “If we knock out something like zooplankton, the base of our marine food web, we’d be more worried about impacts on fish stocks and the ability to feed the world’s population.”

Human studies

No published study has yet directly examined the effects of plastic specks on people, leading researchers say. The only available studies rely on laboratory experiments that expose cells or human tissues to microplastics, or use animals such as mice or rats. In one study7, for instance, mice fed large quantities of microplastics showed inflammation in their small intestines. Mice exposed to microplastics in two studies had a lowered sperm count8 and fewer, smaller pups9, compared with control groups. Some of the in vitro studies on human cells or tissues also suggest toxicity. But, just as with the marine studies, it’s not clear that the concentrations used are relevant to what mice — or people — are exposed to. Most of the studies also used polystyrene spheres, which don’t represent the diversity of microplastics that people ingest. Koelmans also points out that these studies are among the first of their kind, and could end up being outliers once there’s an established body of evidence. There are more in vitro studies than animal studies, but researchers say they still don’t know how to extrapolate the effects of solid plastic specks on tissues to possible health problems in whole animals.

One question surrounding risk is whether microplastics could remain in the human body, potentially accumulating in some tissues. Studies in mice have found that microplastics around 5 µm across could stay in the intestines or reach the liver. Using very limited data on how quickly mice excrete microplastics and the assumption that only a fraction of particles 1–10 µm in size would be absorbed into the body through the gut, Koelmans and colleagues estimate that a person might accumulate several thousand microplastic particles in their body over their lifetime2.

Some researchers have started to explore whether microplastics can be found in human tissue. In December, a team documented this for the first time in a study that looked at six placentas10. Researchers broke down the tissue with a chemical, then examined what was left, and ended up with 12 particles of microplastic in 4 of those placentas. Yet it’s not impossible that these specks were the result of contamination when the placentas were collected or analysed, says Rolf Halden, an environmental-health engineer at Arizona State University in Tempe — although he commends the researchers for their efforts to avoid contamination, which included keeping delivery wards free of plastic objects, and for showing that a control set of blank materials taken through the same sample analysis was not contaminated. “There is a continuing challenge of demonstrating conclusively that a given particle actually originated in a tissue,” he says.

Those who are worried by their microplastic exposure can reduce it, says Li. His work on kitchenware found that the amounts of plastic shed depend highly on temperature — which is why he’s stopped microwaving food in plastic containers. To reduce issues with baby bottles, his team suggests that parents could rinse sterilized bottles with cool water that has been boiled in non-plastic kettles, so as to wash away any microplastics released during sterilization. And they can prepare baby formula in glass containers, filling feeding bottles after the milk has cooled. The team is now recruiting parents to volunteer samples of their babies’ urine and stools for microplastic analysis.

The nano fraction


Particles that are small enough to penetrate and hang around in tissues, or even cells, are the most worrying kind, and warrant more attention in environmental sampling, says Halden. One study11 that deliberately let pregnant mice inhale extremely tiny particles, for instance, later found the particles in almost every organ in their fetuses. “From a risk perspective, that’s where the real concern is, and that’s where we need more data.”

To enter cells, particles generally need to be smaller than a few hundred nanometres. There was no formal definition of a nanoplastic until 2018, when French researchers proposed the upper size limit of 1 µm — tiny enough to remain dispersed through a water column where organisms can more easily consume them, instead of sinking or floating as larger microplastics do, says Alexandra ter Halle, an analytical chemist at Paul Sabatier University in Toulouse, France.

But researchers know almost nothing about nanoplastics; they are invisible and cannot simply be scooped up. Just measuring them has stumped scientists.

Researchers can use optical microscopes and spectrometers — which distinguish between particles by their differing interactions with light — to measure the length, width and chemical make-up of plastic particles down to a few micrometres. Below that scale, plastic particles become difficult to distinguish from non-plastic particles such as marine sediment or biological cells. “You’re looking for the needle in the haystack, but the needle looks like the hay,” says Roman Lehner, a nanomaterials scientist at the Sail and Explore Association, a Swiss non-profit research group.

In 2017, ter Halle and her colleagues proved for the first time that nanoplastic exists in an environmental sample: seawater collected from the Atlantic Ocean12. She extracted colloidal solids from the water, filtered away any particles larger than 1 µm, burnt what remained, and used a mass spectrometer — which fragments molecules and sorts the fragments by molecular weight — to confirm that plastic polymers had existed in the remnants.

That, however, gave no information on the exact sizes or shapes of the nanoplastics. Ter Halle got some idea by studying the surfaces of two degraded plastic containers she collected during the expedition. The top few hundred micrometres had become crystalline and brittle, she found; she thinks that this may also be true of the nanoplastics that probably broke off from these surfaces13. For now, because researchers cannot collect nanoplastics from the environment, those doing laboratory studies grind up their own plastic, expecting to get similar particles.

Using home-made nanoplastics has an advantage: researchers can introduce tags to help track the particles inside test organisms. Lehner and colleagues prepared fluorescent nano-sized plastic particles and placed them under tissue built from human intestinal-lining cells14. The cells did absorb the particles, but did not show signs of cytotoxicity.

Finding plastic specks lodged in intact slices of tissue — through a biopsy, for instance — and observing any pathological effects would be the final piece of the puzzle over microplastic risks, Lehner says. This would be “highly desirable”, says Halden. But to reach tissues, the particles would have to be very small, so both researchers think it would be very difficult to detect them conclusively.

Collecting all these data will take a lot of time. Ter Halle has collaborated with ecologists to quantify microplastic ingestion in the wild. Analysing only particles larger than 700 µm in some 800 samples of insects and fish took thousands of hours, she said. The researchers are now examining the particles in the 25–700 µm range. “This is difficult and tedious, and this is going to take a long time to get the results,” she says. To look at the smaller size range, she adds, “the effort is exponential.”

No time to lose


For the moment, levels of microplastics and nanoplastics in the environment are too low to affect human health, researchers think. But their numbers will rise. Last September, researchers projected15 that the amount of plastic added to existing waste each year — whether carefully disposed of in sealed landfills or strewn across land and sea — could more than double from 188 million tonnes in 2016 to 380 million tonnes in 2040. By then, around 10 million tonnes of this could be in the form of microplastics, the scientists estimated — a calculation that didn’t include the particles continually being eroded from existing waste.

It is possible to rein in some of our plastic waste, says Winnie Lau at the Pew Charitable Trusts in Washington DC, who is the first author on the study. The researchers found that if every proven solution to curb plastic pollution were adopted in 2020 and scaled up as quickly as possible — including switching to systems of reuse, adopting alternative materials, and recycling plastic — the amount of plastic waste added could drop to 140 million tonnes per year by 2040.

By far the biggest gains would come from cutting out plastics that are used only once and discarded. “There’s no point producing things that last for 500 years and then using them for 20 minutes,” Galloway says. “It’s a completely unsustainable way of being.”
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Re: Tiny plastic particles in the environment

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An 18-year-old has found a way to use 'magnetic liquid' invented by NASA to remove harmful microplastics from water

8/1/19


https://www.businessinsider.com/micropl ... gle-2019-8


Microplastics, or tiny bits of plastic less than 5 millimeters long, accumulate in wastewater before filtering into larger bodies of water likes rivers and oceans.
At age 18, Fionn Ferreira developed a method for removing these harmful plastic particles using a liquid invented by NASA.
Ferreira introduced his concept at this year's Google Science Fair. He won the competition and its $50,000 prize.

Fionn Ferreira lives on a remote island in West Cork, a seaside region in southern Ireland. One day while kayaking, he spotted a rock on the shore that was coated in oil from a recent spill. Attached to the rock were tiny bits of plastic less than 5 millimeters long — what scientists call "microplastics."

Because microplastics are so small — about the size of a sesame seed — scientists have struggled to find ways to remove them from the environment. But Ferreira discovered something when he saw the oil-coated rock on the shore.

"It got me thinking," Ferreira said. "In chemistry, like attracts like."

Plastic and oil are nonpolar, meaning they're likely to stick to one another in nature. As a budding scientist, Ferreira had a hunch that the same effect could be created using a magnetic liquid found in speakers and electronic devices.

On Monday, Ferreira won the Google Science Fair's $50,000 grand prize for his experiment, which showed that the liquid could extract microplastics from water.

Microplastics are dangerous to marine life and may have consequences for human health

Microplastic fragments come from a variety of sources, including beauty products, toothpaste, and microfiber towels, as well as larger pieces of plastic that have broken down over time. As a result, microplastics often accumulate in bodies of water like the ocean near Ferreira's home, posing a danger to marine life.

They can also end up in our food and water. Scientists have estimated that Americans consume up to 52,000 microplastic particles each year, but the consequences for human health are still unknown.

One of the main concerns is that microplastics could carry toxic chemicals like phthalates and bisphenol A (BPA) into our bodies. These chemicals have been linked to cancer and reproductive issues.

A 'magnetic liquid' invented by NASA can collect microplastic from water

In 1963, the NASA engineer Steve Papell came up with a way to make rocket fuel magnetic so that it could move around in zero gravity during the Apollo missions. In the process, he wound up creating the first ferrofluid, essentially a magnetic liquid.

Today, the substance helps control vibrations in speakers and seal off electronics so they don't become clogged with debris. It's also a key part of Ferreira's plan to remove microplastics from water.

"I absolutely love ferrofluid," said Ferreira, who makes his own version of the liquid by suspending magnetite powder — a mineral found naturally on Earth's surface — in vegetable oil. (The leftover oil from fast-food chains like McDonald's works well, he said.)

Unlike rocket fuel, Ferreira's mixture isn't harmful to the environment, but it does attract plastic from all types of water, including rivers and oceans.

Ferreira said the most unique part of his mixture is that it can be used to remove plastic from wastewater — water discarded from homes, businesses, and industrial plants, for example. Studies have found that the world's wastewater treatment plants aren't equipped to filter out microplastics, even though they're major contributors to microplastic pollution.

Ferreira just won first place in the Google Science Fair

For his experiment, Ferreira injected ferrofluid into small glasses of water contaminated with microplastics. At first, the water turned black because of the magnetite, but when Ferreira placed a magnet inside the glass, it started to soak up all the fluid. Eventually, the water inside the glass was clear and mostly free of plastic.

Before embarking on his experiment, Ferreira wagered that his magnetic liquid could remove at least 85% of microplastics from his water samples. He wound up removing around 88%.

Of the 10 microplastics he tested, the most difficult fibers to remove came from polypropylene, a type of plastic used in product packaging, Ferreira said. But even then, Ferreira removed about 80% of polypropylene plastics, on average.

The easiest fibers to remove, he said, were those released by washing-machine filters. Ferreira said that's an important finding because washing machines are a common source of microplastic pollution.

After traveling to Mountain View, California, for the science fair, Ferreira is now back in Ireland, recovering from jet lag.

"I still really can't believe it," he said of the competition. "There are lots of different emotions in my head at the moment."

Later this year, Ferreira will begin studying at the University of Groningen in the Netherlands, a research institution below sea level. ("What's cooler than being at a university that's 6 meters under the surface of the sea?" he said.)

Meanwhile, he'll try to deploy his concept for treating wastewater.

"I'm not saying that my project is the solution," he said. "The solution is that we stop using plastic altogether."
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Re: Tiny plastic particles in the environment

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14 Million Tons of Microplastic are on the Ocean Floor

10/19/20


https://sitn.hms.harvard.edu/flash/2020 ... ean-floor/


Many know that plastics in the ocean is a huge problem. They can accumulate in areas over twice the size of Texas, and microplastics in particular (plastics that break down into pieces of less than 5 mm) can harm marine organisms when ingested. However, while researchers have a good understanding of the role of plastics at the surface of the ocean, few have determined just how much plastic actually reaches the seabed of the ocean, a difficult and costly problem given the depth of the ocean.

Researchers Justine Barrett, Chris Wilcox, and their team at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), an Australian Government agency, quantified the amount of microplastics in the Great Australian Bight, a large ocean area south of Australia that is home to many marine species. The researchers utilized a remotely operated vehicle to collect samples from around 1600 to 3000 meters deep in the ocean. They then adapted a characterization technique to filter and purify these deep ocean samples to better evaluate the amount of plastic they contain.

Using careful microscope images, the CSIRO team counted the number of microplastic particles in different samples and estimated based on the counts from this region that 14 million tons of microplastic exist on the whole ocean floor. Previous comparable studies found higher microplastic estimates because they were conducted in coastal areas with higher population densities. This resulted in more pollution or contamination of the samples collected, and therefore was not representative of the majority of the ocean. Because this team’s microplastic count was collected from a more remote location, their total count was lower and provides a more conservative estimate.

This research from Barrett’s team has significant implications for understanding the gravity of the plastics problem in the ocean. Many before have focused on the idea that plastics float on the surface of the ocean, with researchers only beginning to explore the idea of their role in the deep sea. However, these findings show that the deep ocean can serve as a sink for plastics, with even this more conservative estimate revealing a serious problem. We need to act faster to ban plastic dumping to prevent such accumulations.
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Re: Tiny plastic particles in the environment

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We Know Plastic Is Harming Marine Life. What About Us?

There often are tiny bits of plastic in the fish and shellfish we eat. Scientists are racing to figure out what that means for our health.


https://www.nationalgeographic.com/maga ... roplastics


In a laboratory at Columbia University’s Lamont-Doherty Earth Observatory, in Palisades, New York, Debra Lee Magadini positions a slide under a microscope and flicks on an ultraviolet light. Scrutinizing the liquefied digestive tract of a shrimp she bought at a fish market, she makes a tsk-ing sound. After examining every millimeter of the slide, she blurts, “This shrimp is fiber city!” Inside its gut, seven squiggles of plastic, dyed with Nile red stain, fluoresce.

All over the world, researchers like Magadini are staring through microscopes at tiny pieces of plastic—fibers, fragments, or microbeads—that have made their way into marine and freshwater species, both wild caught and farmed. Scientists have found microplastics in 114 aquatic species, and more than half of those end up on our dinner plates. Now they are trying to determine what that means for human health.

So far science lacks evidence that microplastics—pieces smaller than one-fifth of an inch—are affecting fish at the population level. Our food supply doesn’t seem to be under threat—at least as far as we know. But enough research has been done now to show that the fish and shellfish we enjoy are suffering from the omnipresence of this plastic. Every year five million to 14 million tons flow into our oceans from coastal areas. Sunlight, wind, waves, and heat break down that material into smaller bits that look—to plankton, bivalves, fish, and even whales—a lot like food.

Experiments show that microplastics damage aquatic creatures, as well as turtles and birds: They block digestive tracts, diminish the urge to eat, and alter feeding behavior, all of which reduce growth and reproductive output. Their stomachs stuffed with plastic, some species starve and die.

In addition to mechanical effects, microplastics have chemical impacts, because free-floating pollutants that wash off the land and into our seas—such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals—tend to adhere to their surfaces.

Chelsea Rochman, a professor of ecology at the University of Toronto, soaked ground-up polyethylene, which is used to make some types of plastic bags, in San Diego Bay for three months. She then offered this contaminated plastic, along with a laboratory diet, to Japanese medakas, small fish commonly used for research, for two months. The fish that had ingested the treated plastic suffered more liver damage than those that had consumed virgin plastic. (Fish with compromised livers are less able to metabolize drugs, pesticides, and other pollutants.) Another experiment demonstrated that oysters exposed to tiny pieces of polystyrene—the stuff of take-out food containers—produce fewer eggs and less motile sperm.

The list of freshwater and marine organisms that are harmed by plastics stretches to hundreds of species.

It's difficult to parse whether microplastics affect us as individual consumers of seafood, because we’re steeped in this material—from the air we breathe to both the tap and bottled water we drink, the food we eat, and the clothing we wear. Moreover, plastic isn’t one thing. It comes in many forms and contains a wide range of additives—pigments, ultraviolet stabilizers, water repellents, flame retardants, stiffeners such as bisphenol A (BPA), and softeners called phthalates—that can leach into their surroundings.

Some of these chemicals are considered endocrine disruptors—chemicals that interfere with normal hormone function, even contributing to weight gain. Flame retardants may interfere with brain development in fetuses and children; other compounds that cling to plastics can cause cancer or birth defects. A basic tenet of toxicology holds that the dose makes the poison, but many of these chemicals—BPA and its close relatives, for example—appear to impair lab animals at levels some governments consider safe for humans.

Studying the impacts of marine microplastics on human health is challenging because people can’t be asked to eat plastics for experiments, because plastics and their additives act differently depending on physical and chemical contexts, and because their characteristics may change as creatures along the food chain consume, metabolize, or excrete them. We know virtually nothing about how food processing or cooking affects the toxicity of plastics in aquatic organisms or what level of contamination might hurt us.

The good news is that most microplastics studied by scientists seem to remain in the guts of fish and do not move into muscle tissue, which is what we eat. The United Nations Food and Agriculture Organization, in a thick report on this subject, concludes that people likely consume only negligible amounts of microplastics—even those who eat a lot of mussels and oysters, which are eaten whole. The agency reminds us, also, that eating fish is good for us: It reduces the risk of cardiovascular disease, and fish contain high levels of nutrients uncommon in other foods.

That said, scientists remain concerned about the human-health impacts of marine plastics because, again, they are ubiquitous and they eventually will degrade and fragment into nanoplastics, which measure less than 100 billionths of a meter—in other words, they are invisible. Alarmingly these tiny plastics can penetrate cells and move into tissues and organs. But because researchers lack analytical methods to identify nanoplastics in food, they don’t have any data on their occurrence or absorption by humans.

And so the work continues. “We know that there are effects from plastics on animals at nearly all levels of biological organization,” Rochman says. “We know enough to act to reduce plastic pollution from entering the oceans, lakes, and rivers.” Nations can enact bans on certain types of plastic, focusing on those that are the most abundant and problematic. Chemical engineers can formulate polymers that biodegrade. Consumers can eschew single-use plastics. And industry and government can invest in infrastructure to capture and recycle these materials before they reach the water.

In a dusty basement a short distance from the lab where Magadini works, metal shelves hold jars containing roughly 10,000 preserved mummichogs and banded killifish, trapped over seven years in nearby marshes. Examining each fish for the presence of microplastics is a daunting task, but Magadini and her colleagues are keen to see how levels of exposure have changed over time. Others will painstakingly untangle how microbeads, fibers, and fragments affect these forage fish, the larger fish that consume them, and—ultimately—us.

“I think we’ll know the answers in five to 10 years’ time,” Magadini says.

By then at least another 25 million tons of plastic will have flowed into our seas.
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Re: Tiny plastic particles in the environment

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New Study: 15.5 Million Tons of Microplastics Litter Ocean Floor

10/6/20


https://www.ecowatch.com/microplastics- ... 15149.html


Microplastics can be found everywhere from Antarctica to the Pyrenees. A significant amount of plastic waste ends up in the ocean, but very little has been known about how much ends up on the ocean floor — until now.

A new study has found that the ocean floor contains nearly 15.5 tons of microplastics, CNN reported.

Researchers from Australia's government science agency, the Commonwealth Scientific and Industrial Research Organization (CSIRO), examined microplastics on the ocean floor near the Great Australian Bight, a large expanse that comprises the bulk of the country's southwest coastline.

The researchers used a robotic submarine to gather and analyze samples taken from six locations up to 236 miles off the coast, and up to almost 10,000 feet deep, reported CNN.

The results, which were published Monday in Frontiers in Marine Science, revealed about 35 times more plastic at the bottom of the ocean than floating at the surface. In 51 samples taken between March and April 2017, researchers found an average of 1.26 microplastic pieces per gram of sediment, a concentration that's up to 25 times greater than any previous deep-sea study, CNN reported.

"Plastic pollution that ends up in the ocean deteriorates and breaks down, ending up as microplastics," Justine Barrett from CSIRO's Oceans and Atmosphere, who led the study, said in a statement in CNN. "The results show microplastics are indeed sinking to the ocean floor."

Dr. Denise Hardesty, a principal research scientist at CSIRO and a co-author of the research, told The Guardian that finding microplastics in such remote locations and depths reveals the extent of global plastic pollution.

"This means it's throughout the water column. This gives us pause for thought about the world we live in and the impact of our consumer habits on what's considered a most pristine place," Dr. Hardesty told The Guardian. "We need to make sure the big blue is not a big trash pit. This is more evidence that we need to stop this at the source."

The World Economic Forum has estimated that an entire garbage truck full of plastic is dumped into the ocean every minute, every day, The New Daily reported.
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Microplastics Are a Big—and Growing—Part of Global Pollution
But existing solutions, if widely implemented, could significantly reduce the problem by 2040

4/30/21

https://www.pewtrusts.org/en/research-a ... -pollution


Ocean plastic pollution is an urgent and global problem. The Pew Charitable Trusts’ recent report, “Breaking the Plastic Wave,” and accompanying paper in the journal Science, provides the results of an ambitious modeling effort to understand how plastic production, use, and disposal contribute to this issue. Most of the attention paid to the issue has focused on daily-use goods such as food and consumer product packaging. However, Pew found that tiny fragments known as microplastics make up significant amounts of ocean plastic pollution that are often not accounted for in pollution estimates or possible solutions.

Our report found that in 2016, four sources of microplastics alone accounted for 1.3 million metric tons (Mt)—or 11%—of total ocean plastic pollution. These were microbeads used in personal care products such as face scrubs and body washes; the breakdown of plastic fibers caused when synthetic textiles are washed; plastic pellets, also known as nurdles, that are used in the production of almost every plastic item; and the wear and tear of car tires, with this final source making up more than three quarters (78%) of microplastic pollution in the ocean. Notably, high-income countries are the main contributors, accounting for more than one-third of the global total of the above microplastics in 2016. Without immediate changes, the data shows ocean microplastic pollution will more than double to 3 Mt a year in 2040.

What are microplastics?

Although there is no standard definition of microplastics, they are commonly defined as plastic particles smaller than 5 millimeters—about the diameter of a standard pencil eraser. Despite their size, studies have shown that microplastics are major contributors to plastic pollution and are found widely in the environment—from high up Mount Everest to the deep sea—and even in humans and other animals. A recent study, for example, showed that a chemical associated with tire wear microplastics was responsible for die-offs of already at-risk salmon in the U.S. Pacific Northwest.

Of course, preventing such tiny particles from entering the environment is a huge challenge because they are not uniform in shape, size, or type of plastic. For example, polyester microfibers are comparatively lightweight and can float in the air, while tire microplastics are heavier and may be washed from roads to streams to the ocean by rain.

Understanding how different types of microplastics are generated and become pollution requires information on their production and use, on how frequently they are formed from larger plastics, and on where they are found in the environment once they are released. Pew looked at only four types of microplastics. These are known to be significant contributors to plastic pollution, but there are many other types of microplastics for which not enough data is available to analyze. For example, the European Union recently published an inventory of microplastics that are added to products, along with a proposal to restrict their use in nine product categories, including detergents and plastic coatings used for seeds and commercial-grade fertilizers. Unfortunately, such information is not available for most other countries and regions in the world.

What are the solutions?

“Breaking the Plastic Wave” found that there are some simple solutions to the microplastics problem, such as replacing microbeads in personal care products with natural materials such as nut shells. For the other three sources, real system change—that is, a new approach to how we produce, use, and dispose of plastic, including microplastic—will be required. For tires, improving design and reducing the number of miles driven, for example by increasing use of public transport instead of individual/private cars, can nearly halve microplastic pollution from tires by 2040. Likewise, ensuring robust implementation of pellet management plans and procedures can reduce plastic pellet pollution by 80% by 2040. And for textiles, redesigning fabrics to minimize microfiber shedding and installing in-line filters in washing machines can contribute to a 77% decrease in this type of pollution in the same period.

Alarming studies regularly come out with new information about the impacts and growing scale of the microplastics problem, but there is still hope for fixing it. With concerted action that begins now, we can greatly reduce the plastic pollution flowing into our lands, rivers, and oceans over the next two decades.
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Bacteria-sized robots take on microplastics and win by breaking them down

6/9/21


https://phys.org/news/2021-06-bacteria- ... stics.html


Small pieces of plastic are everywhere, stretching from urban environments to pristine wilderness. Left to their own devices, it can take hundreds of years for them to degrade completely. Catalysts activated by sunlight could speed up the process, but getting these compounds to interact with microplastics is difficult. In a proof-of-concept study, researchers reporting in ACS Applied Materials & Interfaces developed self-propelled microrobots that can swim, attach to plastics and break them down.

While plastic products are omnipresent indoors, plastic waste and broken bits now litter the outdoors, too. The smallest of these—microplastics less than 5 mm in size—are hard to pick up and remove. In addition, they can adsorb heavy metals and pollutants, potentially harming humans or animals if accidently consumed. So, previous researchers proposed a low-energy way to get rid of plastics in the environment by using catalysts that use sunlight to produce highly reactive compounds that break down these types of polymers. However, getting the catalysts and tiny plastic pieces in contact with each other is challenging and usually requires pretreatments or bulky mechanical stirrers, which aren't easily scaled-up. Martin Pumera and colleagues wanted to create a sunlight-propelled catalyst that moves toward and latches onto microparticles and dismantles them.

To transform a catalytic material into light-driven microrobots, the researchers made star-shaped particles of bismuth vanadate and then evenly coated the 4–8 µm-wide structures with magnetic iron oxide. The microrobots could swim down a maze of channels and interact with microplastic pieces along their entire lengths. The researchers found that under visible light, microrobots strongly glommed on to four common types of plastics. The team then illuminated pieces of the four plastics covered with the microrobot catalyst for seven days in a dilute hydrogen peroxide solution. They observed that the plastic lost 3% of its weight and that the surface texture for all types changed from smooth to pitted, and small molecules and components of the plastics were found in the left-over solution. The researchers say the self-propelled microrobot catalysts pave the way toward systems that can capture and degrade microplastics in hard-to-reach-locations.

More information: Seyyed Mohsen Beladi-Mousavi et al, A Maze in Plastic Wastes: Autonomous Motile Photocatalytic Microrobots against Microplastics, ACS Applied Materials & Interfaces (2021). DOI: 10.1021/acsami.1c04559
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