Every breath you take: Study models the journey of inhaled plastic particle pollution

With recent studies having established the presence of nano and microplastic particles in the respiratory systems of both human and bird populations, a new University of Technology Sydney (UTS) study has modelled what happens when people breathe in different kinds of plastic particles and where they end up.

Led by Senior Lecturer of Mechanical Engineering Dr Suvash Saha, the UTS research team has used computational fluid-particle dynamics (CFPD) to study the transfer and deposition of particles of different sizes and shapes depending on the rate of breathing.

The results of the modelling, published in the journal Environmental Advances, have pinpointed hotspots in the human respiratory system where plastic particles can accumulate, from the nasal cavity and larynx and into the lungs.

Dr Saha said evidence was mounting on the significant impact of nano and microplastics on respiratory health and the UTS study would provide essential insights for the development of targeted strategies to mitigate potential risks and ensure effective health interventions.

"Experimental evidence has strongly suggested that these plastic particles amplify human susceptibility to a spectrum of lung disorders, including chronic obstructive pulmonary disease, fibrosis, dyspnea (shortness of breath), asthma, and the formation of what are called frosted glass nodules," Dr Saha said.

"Plastic particle air pollution is now pervasive and inhalation ranks as the second most likely pathway for human exposure.

"The primary types are intentionally manufactured, including a wide array of cosmetics and personal care products such as toothpaste.

"The secondary ones are fragments derived from the degradation of larger plastic products, such as water bottles, food containers and clothes.

"Extensive investigations have identified synthetic textiles as a principal source of indoor airborne plastic particles, while the outdoor environment presents a multitude of sources encompassing contaminated aerosols from the ocean to particles originating from wastewater treatment."

Dr Saha said the UTS team's modelling found that breathing rate along with particle size and shape determined where in the respiratory system plastic particles would be deposited.

"Faster breathing rates led to heightened deposition in the upper respiratory tract, particularly for larger microplastics, whereas slower breathing facilitated deeper penetration and deposition of smaller nanoplastic particles," he said.

"Particle shape was another factor, with non-spherical microplastic particles showing a propensity for deeper lung penetration compared to spherical microplastics and nanoplastics, potentially leading to different health outcomes.

Read more at Science Daily

Microplastics make their way from the gut to other organs

It's happening every day. From our water, our food and even the air we breathe, tiny plastic particles are finding their way into many parts of our body.

But what happens once those particles are inside? What do they do to our digestive system?

In a recent paper published in the journal Environmental Health Perspectives, University of New Mexico researchers found that those tiny particles -- microplastics -- are having a significant impact on our digestive pathways, making their way from the gut and into the tissues of the kidney, liver and brain.

Eliseo Castillo, PhD, an associate professor in the Division of Gastroenterology & Hepatology in the UNM School of Medicine's Department of Internal Medicine and an expert in mucosal immunology, is leading the charge at UNM on microplastic research.

"Over the past few decades, microplastics have been found in the ocean, in animals and plants, in tap water and bottled water," Castillo, says. "They appear to be everywhere."

Scientists estimate that people ingest 5 grams of microplastic particles each week on average -- equivalent to the weight of a credit card.

While other researchers are helping to identify and quantify ingested microplastics, Castillo and his team focus on what the microplastics are doing inside the body, specifically to the gastrointestinal (GI) tract and to the gut immune system.

Over a four-week period, Castillo, postdoctoral fellow Marcus Garcia, PharmD, and other UNM researchers exposed mice to microplastics in their drinking water. The amount was equivalent to the quantity of microplastics humans are believed to ingest each week.

Microplastics had migrated out of the gut into the tissues of the liver, kidney and even the brain, the team found. The study also showed the microplastics changed metabolic pathways in the affected tissues.

"We could detect microplastics in certain tissues after the exposure," Castillo says. "That tells us it can cross the intestinal barrier and infiltrate into other tissues."

Castillo says he's also concerned about the accumulation of the plastic particles in the human body. "These mice were exposed for four weeks," he says. "Now, think about how that equates to humans, if we're exposed from birth to old age."

The healthy laboratory animals used in this study showed changes after brief microplastic exposure, Castillo says. "Now imagine if someone has an underlying condition, and these changes occur, could microplastic exposure exacerbate an underlying condition?"

He has previously found that microplastics are also impacting macrophages -- the immune cells that work to protect the body from foreign particles.

In a paper published in the journal Cell Biology & Toxicology in 2021, Castillo and other UNM researchers found that when macrophages encountered and ingested microplastics, their function was altered and they released inflammatory molecules.

"It is changing the metabolism of the cells, which can alter inflammatory responses," Castillo says. "During intestinal inflammation -- states of chronic illness such as ulcerative colitis and Crohn's disease, which are both forms of inflammatory bowel disease -- these macrophages become more inflammatory and they're more abundant in the gut."

The next phase of Castillo's research, which is being led by postdoctoral fellow Sumira Phatak, PhD, will explore how diet is involved in microplastic uptake.

"Everyone's diet is different," he says. "So, what we're going to do is give these laboratory animals a high-cholesterol/high-fat diet, or high-fiber diet, and they will be either exposed or not exposed to microplastics. The goal is to try to understand if diet affects the uptake of microplastics into our body."

Castillo says one of his PhD students, Aaron Romero, is also working to understand why there is a change in the gut microbiota. "Multiple groups have shown microplastics change the microbiota, but how it changes the microbiota hasn't been addressed."

Castillo hopes that his research will help uncover the potential impacts microplastics are having to human health and that it will help spur changes to how society produces and filtrates plastics.

Read more at Science Daily

Tiny plastic particles are found everywhere

It's not the first study on microplastics in Antarctica that researchers from the University of Basel and the Alfred-Wegener Institute (AWI) have conducted. But analysis of the data from an expedition in spring 2021 shows that environmental pollution from these tiny plastic particles is a bigger problem in the remote Weddell Sea than was previously known.

The total of 17 seawater samples all indicated higher concentrations of microplastics than in previous studies. "The reason for this is the type of sampling we conducted," says Clara Leistenschneider, doctoral candidate in the Department of Environmental Sciences at the University of Basel and lead author of the study.

The current study focused on particles measuring between 11 and 500 micrometers in size. The researchers collected them by pumping water into tanks, filtering it, and then analyzing it using infrared spectroscopy. Previous studies in the region had mostly collected microplastic particles out of the ocean using fine nets with a mesh size of around 300 micrometers. Smaller particles would simply pass through these plankton nets.

The results of the new study indicate that 98.3 percent of the plastic particles present in the water were smaller than 300 micrometers, meaning that they were not collected in previous samples. "Pollution in the Antarctic Ocean goes far beyond what was reported in past studies," Leistenschneider notes. The study appears in the journal Science of the Total Environment.

What role do ocean currents play?

The individual samples were polluted to different extents. The offshore samples, which were collected north of the continental slope and the Antarctic Slope Current, contained the highest concentrations of microplastics. The reasons for this are not conclusively known. It may be that the ice that tends to form near the coast retains the tiny plastic particles, and they are only released back into the water when the ice melts. It could also be the case that ocean currents play a role. "They might work like a barrier, reducing water exchange between the north and south," suggests Gunnar Gerdts from the AWI in Heligoland, Germany.

What is certainly true is that ocean currents are an important factor and the subject of many open questions in the field. So far the researchers have only examined water samples from the ocean surface, but not from lower depths. This is primarily due to limited time on the ship expeditions for taking samples and to equipment with insufficient pumping capacity. "It would nonetheless be revealing to analyze such data, since the deep currents differ greatly from the surface currents and thermohaline circulation leads to exchange with water masses from northern regions," Leistenschneider says.

It is also still unclear how the microplastics make their way to the Weddell Sea in the first place and whether they ever leave the region. The strong Antarctic Circumpolar Current, which flows all the way around the Antarctic Ocean at a latitude of about 60° south, might prevent their departure. The researchers are also not yet able to say conclusively where the microplastics originate. Possible sources include regional ship traffic from the tourism, fishing and research industries, as well as research stations on land. However, the microplastics might also make their way to Antarctica from other regions via ocean currents or atmospheric transport.

Research leads to awareness

Clara Leistenschneider plans to focus next on analyzing the sediment samples she collected during the same expedition. This should provide information about how microplastics are accumulating on the sea floor, which is home to unique and sensitive organisms and is a breeding ground for Antarctic icefish (Bovichtidae).

With the increase in tourism in the Antarctic Ocean, pollution may increase even more in the future, further impacting the environment and the food chain.

Read more at Science Daily

Microplastic 'hotspots' identified in Long Island Sound

Forensic and environmental experts have teamed up to develop a new scientific method to pinpoint microplastic pollution 'hotspots' in open waters.

A study by Staffordshire University, The Rozalia Project for a Clean Ocean and Central Wyoming College trialled the technique in New York's Long Island Sound.

Professor Claire Gwinnett from Staffordshire University explained: "Long Island Sound was a location of interest because it has lots of factors that can cause pollution.

"It is an estuary that has high populations of wildlife, it is a busy transport route frequented by cargo ships and is a popular fishing area. Located adjacent to New York City, it is also highly populated and a major tourist destination."

Funded, in part, by the National Geographic Society, the study saw samples collected from the deck of the 60′ oceanographic sailing research vessel, American Promise. The team took 1 litre 'grab samples' of surface water every 3 miles from the East River along the middle of Long Island Sound to The Race, where it meets Rhode Island Sound.

Grab sampling allows analysis of specific locations, with the researchers applying a statistical approach to identify hotspots where microplastics were most in evidence.

"People often use the term 'hotspot' but it is not scientifically defined. Previous studies have used largely subjective methods, without the use of any rules or thresholds that differentiate hotspots from non-hotspots," Professor Gwinnett commented.

"Our study proposed a simple yet objective method for determining hotspots using standard deviation values. This is the first time that this has been done."

Two primary and two secondary hotspots were observed, near either end of the sampling area. There is potentially a "bottleneck" effect in the narrower zones or, conversely, a dilution effect in the wider section of Long Island Sound. Similarly, hotspots were observed as being close to or in line with a river mouth, specifically the Thames and Connecticut Rivers.

Overlaying heat maps of various types of shipping and vessel traffic with the microparticle heat map from this study shows potential similarities. In particular, between areas of high recreational and passenger vessel traffic and higher microplastic concentration.

Professor Gwinnett said: "We need to consider factors that might influence these results, such as population, geography and human use. The identified hotspots, however, were found in both densely populated areas and adjacent to some of the least densely populated land areas surrounding Long Island Sound.

"The first step in combatting this type of pollution is by characterizing microparticle samples so that we can begin to understand where they might have come from."

97% of samples contained human-made particulates. Microparticles were classified as 76.14% fibres and 23.86% fragments. 47.76% of the fibres were synthetic and 52.24% were non-synthetic.

Forensic science approaches developed by Staffordshire University were used to analyse the microparticles -- including type, colour, shape, material, presence of delusterant and width -- which identified 30 unique categories of potential sources of pollution.

Rachael Miller, Expedition lead and Rozalia Project Founder, explained: "Unlike larger fragments of plastic, which may exhibit clear features that easily identify its original source, such as bottle cap ridges or a partial logo, this is generally very difficult for microparticles unless an analysis approach which fully characterizes the particle is used.

"Identifying a specific type of item from which a microparticle came from e.g. pair of jeans, carpet, tyre or personal hygiene product increases the likelihood of discovering the mechanism for transport to the environment. That, in turn, increases opportunities to prevent a subset of microplastic pollution."

The authors are now calling for reference databases of potential pollutants of waterways. PhD researcher Amy Osbourne specialises in forensic fibre analysis at Staffordshire University after progressing from the undergraduate degree in Forensic Investigation.

She said: "We cannot confidently identify the sources of pollution without being able to cross reference samples against large, easily searched known provenance databases. Such databases are already used in forensic science when identifying sources of evidence found at crime scenes.

"For example, we might begin with a database of all the different types of fishing nets or tarpaulins that we know are commonly used in areas like Long Island Sound."

Read more at Science Daily

Scientists uncover evidence that microplastics are contaminating archaeological remains

Researchers have for the first time discovered evidence of microplastic contamination in archaeological soil samples.

The team discovered tiny microplastic particles in deposits located more than seven metres deep, in samples dating back to the first or early second century and excavated in the late 1980s.

Preserving archaeology in situ has been the preferred approach to managing historical sites for a generation.

However, the research team say the findings could prompt a rethink, with the tiny particles potentially compromising the preserved remains.

Microplastics are small plastic particles, ranging from 1μm (one thousandth of a millimetre) to 5mm.

They come from a wide range of sources, from larger plastic pieces that have broken apart, or resin pellets used in plastic manufacturing which were frequently used in beauty products up until around 2020.

The study, published in the journal Science of the Total Environment, was carried out by the universities of York and Hull and supported by the educational charity York Archaeology.

Professor John Schofield from the University of York's Department of Archaeology, said: "This feels like an important moment, confirming what we should have expected: that what were previously thought to be pristine archaeological deposits, ripe for investigation, are in fact contaminated with plastics, and that this includes deposits sampled and stored in the late 1980s.

"We are familiar with plastics in the oceans and in rivers. But here we see our historic heritage incorporating toxic elements. To what extent this contamination compromises the evidential value of these deposits, and their national importance is what we'll try to find out next."

David Jennings, chief executive of York Archaeology, added: "We think of microplastics as a very modern phenomenon, as we have only really been hearing about them for the last 20 years, when Professor Richard Thompson revealed in 2004 that they have been prevalent in our seas since the 1960s with the post-war boom in plastic production,"

"This new study shows that the particles have infiltrated archaeological deposits, and like the oceans, this is likely to have been happening for a similar period, with particles found in soil samples taken and archived in 1988 at Wellington Row in York."

The study identified 16 different microplastic polymer types across both contemporary and archived samples.

"Where this becomes a concern for archaeology is how microplastics may compromise the scientific value of archaeological deposits. Our best-preserved remains -- for example, the Viking finds at Coppergate -- were in a consistent anaerobic waterlogged environment for over 1000 years, which preserved organic materials incredibly well. The presence of microplastics can and will change the chemistry of the soil, potentially introducing elements which will cause the organic remains to decay. If that is the case, preserving archaeology in situ may no longer be appropriate," added David Jennings.

Read more at Science Daily

Say hello to biodegradable microplastics

Microplastics are tiny, nearly indestructible fragments shed from everyday plastic products. As we learn more about microplastics, the news keeps getting worse. Already well-documented in our oceans and soil, we're now discovering them in the unlikeliest of places: our arteries, lungs and even placentas. Microplastics can take anywhere from 100 to 1,000 years to break down and, in the meantime, our planet and bodies are becoming more polluted with these materials every day.

Finding viable alternatives to traditional petroleum-based plastics and microplastics has never been more important. New research from scientists at the University of California San Diego and materials-science company Algenesis shows that their plant-based polymers biodegrade -- even at the microplastic level -- in under seven months. The paper, whose authors are all UC San Diego professors, alumni or former research scientists, appears in Nature Scientific Reports.

"We're just starting to understand the implications of microplastics. We've only scratched the surface of knowing the environmental and health impacts," stated Professor of Chemistry and Biochemistry Michael Burkart, one of the paper's authors and an Algenesis co-founder. "We're trying to find replacements for materials that already exist, and make sure these replacements will biodegrade at the end of their useful life instead of collecting in the environment. That's not easy."

"When we first created these algae-based polymers about six years ago, our intention was always that it be completely biodegradable," said another of the paper's authors, Robert Pomeroy, who is also a professor of chemistry and biochemistry and an Algenesis co-founder. "We had plenty of data to suggest that our material was disappearing in the compost, but this is the first time we've measured it at the microparticle level."

Putting it to the test

To test its biodegradability, the team ground their product into fine microparticles, and used three different measurement tools to confirm that, when placed in a compost, the material was being digested by microbes.

The first tool was a respirometer. When the microbes break down compost material, they release carbon dioxide (CO2), which the respirometer measures. These results were compared to the breakdown of cellulose, which is considered the industry standard of 100% biodegradability. The plant-based polymer matched the cellulose at almost one hundred percent.

Next the team used water flotation. Since plastics are not water soluble and they float, they can easily be scooped off the surface of water. At intervals of 90 and 200 days, almost 100% of the petroleum-based microplastics were recovered, meaning none of it had biodegraded. On the other hand, after 90 days, only 32% of the algae-based microplastics were recovered, showing that more than two thirds of it had biodegraded. After 200 days, only 3% was recovered indicating that 97% of it had disappeared.

The last measurement involved chemical analysis via gas chromatography/mass spectrometry (GCMS), which detected the presence of the monomers used to make the plastic, indicating that the polymer was being broken to its starting plant materials. Scanning-electron microscopy further showed how microorganisms colonize the biodegradable microplastics during composting.

"This material is the first plastic demonstrated to not create microplastics as we use it," said Stephen Mayfield, a paper coauthor, School of Biological Sciences professor and co-founder of Algenesis. "This is more than just a sustainable solution for the end-of-product life cycle and our crowded landfills. This is actually plastic that is not going to make us sick."

Creating an eco-friendly alternative to petroleum-based plastics is only one part of the long road to viability. The ongoing challenge is to be able to use the new material on pre-existing manufacturing equipment that was originally built for traditional plastic, and here Algenesis is making progress. They have partnered with several companies to make products that use the plant-based polymers developed at UC San Diego, including Trelleborg for use in coated fabrics and RhinoShield for use in the production of cell phone cases.

"When we started this work, we were told it was impossible," stated Burkart. "Now we see a different reality. There's a lot of work to be done, but we want to give people hope. It is possible."

Read more at Science Daily

Bottled water can contain hundreds of thousands of previously uncounted tiny plastic bits

In recent years, there has been rising concern that tiny particles known as microplastics are showing up basically everywhere on Earth, from polar ice to soil, drinking water and food. Formed when plastics break down into progressively smaller bits, these particles are being consumed by humans and other creatures, with unknown potential health and ecosystem effects. One big focus of research: bottled water, which has been shown to contain tens of thousands of identifiable fragments in each container.

Now, using newly refined technology, researchers have entered a whole new plastic world: the poorly known realm of nanoplastics, the spawn of microplastics that have broken down even further. For the first time, they counted and identified these minute particles in bottled water. They found that on average, a liter contained some 240,000 detectable plastic fragments -- 10 to 100 times greater than previous estimates, which were based mainly on larger sizes.

The study was just published in the journal Proceedings of the National Academy of Sciences.

Nanoplastics are so tiny that, unlike microplastics, they can pass through intestines and lungs directly into the bloodstream and travel from there to organs including the heart and brain. They can invade individual cells, and cross through the placenta to the bodies of unborn babies. Medical scientists are racing to study the possible effects on a wide variety of biological systems.

"Previously this was just a dark area, uncharted. Toxicity studies were just guessing what's in there," said study coauthor Beizhan Yan, an environmental chemist at Columbia University's Lamont-Doherty Earth Observatory. "This opens a window where we can look into a world that was not exposed to us before."

Worldwide plastic production is approaching 400 million metric tons a year. More than 30 million tons are dumped yearly in water or on land, and many products made with plastics including synthetic textiles shed particles while still in use. Unlike natural organic matter, most plastics do not break down into relatively benign substances; they simply divide and redivide into smaller and smaller particles of the same chemical composition. Beyond single molecules, there is no theoretical limit to how small they can get.

Microplastics are defined as fragments ranging from 5 millimeters (less than a quarter inch) down to 1 micrometer, which is 1 millionth of a meter, or 1/25,000th of an inch. (A human hair is about 70 micrometers across.) Nanoplastics, which are particles below 1 micrometer, are measured in billionths of a meter.

Plastics in bottled water became a public issue largely after a 2018 study detected an average of 325 particles per liter; later studies multiplied that number many times over. Scientists suspected there were even more than they had yet counted, but good estimates stopped at sizes below 1 micrometer -- the boundary of the nano world.

"People developed methods to see nano particles, but they didn't know what they were looking at," said the new study's lead author, Naixin Qian, a Columbia graduate student in chemistry. She noted that previous studies could provide bulk estimates of nano mass, but for the most part could not count individual particles, nor identify which were plastics or something else.

The new study uses a technique called stimulated Raman scattering microscopy, which was co-invented by study coauthor Wei Min, a Columbia biophysicist. This involves probing samples with two simultaneous lasers that are tuned to make specific molecules resonate. Targeting seven common plastics, the researchers created a data-driven algorithm to interpret the results. "It is one thing to detect, but another to know what you are detecting," said Min.

The researchers tested three popular brands of bottled water sold in the United States (they declined to name which ones), analyzing plastic particles down to just 100 nanometers in size. They spotted 110,000 to 370,000 particles in each liter, 90% of which were nanoplastics; the rest were microplastics. They also determined which of the seven specific plastics they were, and charted their shapes -- qualities that could be valuable in biomedical research.

One common one was polyethylene terephthalate or PET. This was not surprising, since that is what many water bottles are made of. (It is also used for bottled sodas, sports drinks and products such as ketchup and mayonnaise.) It probably gets into the water as bits slough off when the bottle is squeezed or gets exposed to heat. One recent study suggests that many particles enter the water when you repeatedly open or close the cap, and tiny bits abrade.

However, PET was outnumbered by polyamide, a type of nylon. Ironically, said Beizhan Yan, that probably comes from plastic filters used to supposedly purify the water before it is bottled. Other common plastics the researchers found: polystyrene, polyvinyl chloride and polymethyl methacrylate, all used in various industrial processes.

A somewhat disturbing thought: the seven plastic types the researchers searched for accounted for only about 10% of all the nanoparticles they found in samples; they have no idea what the rest are. If they are all nanoplastics, that means they could number in the tens of millions per liter. But they could be almost anything, "indicating the complicated particle composition inside the seemingly simple water sample," the authors write. "The common existence of natural organic matter certainly requires prudent distinguishment."

The researchers are now reaching beyond bottled water. "There is a huge world of nanoplastics to be studied," said Min. He noted that by mass, nanoplastics comprise far less than microplastics, but "it's not size that matters. It's the numbers, because the smaller things are, the more easily they can get inside us."

Among other things, the team plans to look at tap water, which also has been shown to contain microplastics, though far less than bottled water. Beizhan Yan is running a project to study microplastics and nanoplastics that end up in wastewater when people do laundry -- by his count so far, millions per 10-pound load, coming off synthetic materials that comprise many items. (He and colleagues are designing filters to reduce the pollution from commercial and residential washing machines.) The team will soon identify particles in snow that British collaborators trekking by foot across western Antarctica are currently collecting. They also are collaborating with environmental health experts to measure nanoplastics in various human tissues and examine their developmental and neurologic effects.

"It is not totally unexpected to find so much of this stuff," said Qian. "The idea is that the smaller things get, the more of them there are."

Read more at Science Daily

First dive survey of Lake Tahoe's lakebed finds high amounts of plastic and other litter

Plastic litter is a growing problem around the world, and new research shows that the bottom of Lake Tahoe is no exception. In one of the first studies to utilize scuba divers to collect litter from a lakebed, 673 plastic items were counted from just a small fraction of the lake.

In the study, published in the November issue of the journal Applied Spectroscopy, researchers from DRI and the UC Davis Tahoe Environmental Research Center teamed up with the nonprofit Clean Up the Lake to take a close look at the litter.

First, scientists broke it down into categories based on use (such as food containers and water bottles), followed by the chemical composition of the plastic.

The knowledge gained can help scientists better understand the source of large pieces of litter in the lake, as well as whether they're a significant source of microplastics as larger pieces break down and degrade.

Previous research found that the waters of Lake Tahoe contain high levels of microplastics, defined as plastics smaller than a pencil eraser.

"There's very little work on submerged plastic litter in lakes," said Monica Arienzo, Ph.D., associate research professor of hydrology at DRI and one of the study's lead authors.

"And I think that's a real issue, because when we think about how plastics may be moving in freshwater systems, there's a good chance that they'll end up in a lake."

To collect the litter, research divers swam transects along the lakebed near Lake Tahoe Nevada State Park and Zephyr Cove, covering 9.3 kilometers.

They found an average of 83 pieces of plastic litter per kilometer, with the lakebed near Hidden Beach and South Sand Harbor showing significantly more (140 items/km and 124 items/km, respectively). No stretches of the lakebed surveyed were free of plastic litter.

The most common plastic litter categories were food containers, bottles, plastic bags, and toys, along with many items that couldn't be categorized.

"There's a lot of education we can do, as well as continuing to work on reducing the use of those plastics," Arienzo says.

"Because we have to start thinking about turning that plastic pipe off."

Arienzo and co-author Julia Davidson, then an undergraduate student working in Arienzo's lab, also identified the types of plastic that made up 516 of the litter samples.

Using an instrument that uses infrared light to fingerprint and identify the material, they found that the six most common plastics were polyvinyl chloride (PVC), polystyrene, polyester/polyethylene terephthalate, polyethylene, polypropylene, and polyamide.

Collecting this information can contribute to Arienzo's ongoing microplastics research in the region, helping to identify the sources of the small plastic fragments.

"When we study microplastics, we only have the chemical information, or the plastic type," Davidson says.

"We don't know where it came from -- a plastic bag, toy, or otherwise -- because it's just a tiny piece of plastic. But now we can use this litter data to point to the dominant types of plastics and compare them to microplastic data."

The study can help inform efforts by Tahoe-area communities to address plastic litter, such as South Lake Tahoe's 2022 ban on single-use plastic bottles and Truckee's ban on single-use food containers.

The research also highlights ways that scientists can work with nonprofits to collect data that can address local environmental concerns.

Read more at Science Daily

Not so silver lining: Microplastics found in clouds could affect the weather

From the depths of the seas to snow on mountains and even the air above cities, microplastics are turning up increasingly often. Now, in ACS' Environmental Science & Technology Letters, researchers have analyzed microplastics in clouds above mountains. They suggest that these tiny particles could play a role in cloud formation and, in turn, affect weather.

Microplastics -- plastic fragments smaller than five millimeters -- originate from a myriad of items used daily, such as clothing, packaging and car tires. As research in the field evolves, scientists are not only detecting microplastics in the atmosphere but also investigating how they may play a role in cloud formation. For example, a group of researchers recently detected plastic granules, which had water-attracting surfaces, in Japanese mountaintop clouds. So, to learn more, Yan Wang and colleagues set out to look for microplastics in mountain clouds, used computer models to figure out how they could have gotten there, and tested how the particles could have impacted -- and been impacted by -- the clouds.

Wang and the team first collected 28 samples of liquid from clouds at the top of Mount Tai in eastern China. Then they analyzed the samples and found:

• Low-altitude and denser clouds contained greater amounts of microplastics.
• Particles were made of common polymers, including polyethylene terephthalate, polypropylene, polyethylene, polystyrene and polyamide.
• The microplastics tended to be smaller than 100 micrometers in length, although some were as long as 1,500 micrometers.
• Older, rougher particles had more lead, mercury and oxygen attached to their surfaces, which the researchers suggest could facilitate cloud development.

To investigate where the plastic particles in the clouds originated, Wang and the team developed computer models that approximated how the particles traveled to Mount Tai. These models suggested that airflow from highly populated inland areas, rather than from over the ocean or other nearby mountains, served as the major source of the fragments. In laboratory experiments, the researchers demonstrated that microplastics exposed to cloud-like conditions -- ultraviolet light and filtered cloud-sourced water -- had smaller sizes and rougher surfaces than those exposed to pure water or air. Additionally, particles impacted by the cloud-like conditions had more lead, mercury and oxygen-containing groups. These results suggest that clouds modify microplastics in ways that could enable the particles to affect cloud formation and the fate of airborne metals. The researchers conclude that more work is needed to fully understand how microplastics affect clouds and the weather.

Read more at Science Daily

Bit by bit, microplastics from tires are polluting our waterways

Urban stormwater particles from tyre wear were the most prevalent microplastic a new Griffith-led study has found.

Published in Environmental Science & Technology, the study showed that in stormwater runoff during rain approximately 19 out of every 20 microplastics collected were tyre wear particles with anywhere from 2 to 59 particles per litre of water.

"Pollution of our waterways by microplastics is an emerging environmental concern due to their persistence and accumulation in aquatic organisms and ecosystems," said lead author Dr Shima Ziajahromi, a research fellow at the Australian Rivers Institute.

"Stormwater runoff which contains a mixture of sediment, chemical, organic and physical pollutants, is a critical pathway for microplastics to washed off from urban environments during rain and into local aquatic habitats.

"But to date, our knowledge of the amount of microplastics in urban stormwater, particularly tyre wear particles, is limited, as is the potential strategies we can use to minimise this source."

Tyre rubber contains up to 2500 chemicals with the contaminants that leach from tyres considered more toxic to bacteria and microalgae than other plastic polymers.

"Due to the analytical challenges in measuring this source of microplastics in stormwater, research to date often lacks information about the actual number of tyre wear particles water samples," said Dr Ziajahromi.

Quantitative information of this type is crucial to improve our understanding of the amount of tyre wear particles in stormwater, assess the risk to the environment, and to develop management strategies.

"Our study quantified and characterize microplastics and tyre wear particles in both stormwater runoff and sediment of stormwater drainage systems in Queensland," said co-author Professor Fred Leusch, who leads the Australian Rivers Institute's Toxicology Research Program.

"We also assessed the effectiveness of a stormwater treatment device to capture and remove these contaminants from stormwater and evaluated the role of a constructed stormwater wetland for capturing microplastics in the sediment, removing it from stormwater runoff.

"The device is a bag made of 0.2 millimetre mesh which can be retrofitted to stormwater drains. Although originally designed to capture gross pollutants, sediment, litter and oil and grease, it significantly reduced microplastics from raw runoff, with up to 88% less microplastics in treated water which had passed through the device."

Sediment samples collected from the inlet and outlet of a constructed stormwater wetland contained between 1450 to 4740 particles in every kilogram of sediment, with more microplastics in the sediment at the inlet than the outlet, indicating the wetland's ability to remove them from stormwater.

"Microplastics that enter constructed wetlands for stormwater drainage systems settle in the sediment and form a biofilm, leading to their accumulation over time, removing them from stormwater runoff," said Dr Ziajahromi.

"Urban stormwater runoff typically requires treatment for the removal of suspended solids and nutrients such as nitrogen and phosphorus in many jurisdictions in Australia, with some also requiring the removal of gross pollutants. However, regulations are lagging behind when it comes to microplastics and tyre wear particles."

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Microplastics infiltrate all systems of body, cause behavioral changes

Plastics -- in particular, microplastics -- are among the most pervasive pollutants on the planet, finding their way into the air, water systems and food chains around the world. While the prevalence of microplastics in the environment is well known -- as are their negative impacts on marine organisms -- few studies have examined the potential health impacts on mammals, prompting University of Rhode Island Professor Jaime Ross' new study.

Ross and her team focused on neurobehavioral effects and inflammatory response to exposure to microplastics, as well as the accumulation of microplastics in tissues, including the brain. They have found that the infiltration of microplastics was as widespread in the body as it is in the environment, leading to behavioral changes, especially in older test subjects.

"Current research suggests that these microplastics are transported throughout the environment and can accumulate in human tissues; however, research on the health effects of microplastics, especially in mammals, is still very limited," said Ross, an assistant professor of biomedical and pharmaceutical sciences at the Ryan Institute for Neuroscience and the College of Pharmacy. "This has led our group to explore the biological and cognitive consequences of exposure to microplastics."

Ross' team -- which includes Research Assistant Professor Giuseppe Coppotelli, biomedical and pharmaceutical sciences graduate student Lauren Gaspar, and Interdisciplinary Neuroscience Program graduate student Sydney Bartman -- exposed young and old mice to varying levels of microplastics in drinking water over the course of three weeks. They found that microplastic exposure induces both behavioral changes and alterations in immune markers in liver and brain tissues. The study mice began to move and behave peculiarly, exhibiting behaviors akin to dementia in humans. The results were even more profound in older animals.

"To us, this was striking. These were not high doses of microplastics, but in only a short period of time, we saw these changes," Ross said. "Nobody really understands the life cycle of these microplastics in the body, so part of what we want to address is the question of what happens as you get older. Are you more susceptible to systemic inflammation from these microplastics as you age? Can your body get rid of them as easily? Do your cells respond differently to these toxins?"

To understand the physiological systems that may be contributing to these changes in behavior, Ross' team investigated how widespread the microplastic exposure was in the body, dissecting several major tissues including the brain, liver, kidney, gastrointestinal tract, heart, spleen and lungs. The researchers found that the particles had begun to bioaccumulate in every organ, including the brain, as well as in bodily waste.

"Given that in this study the microplastics were delivered orally via drinking water, detection in tissues such as the gastrointestinal tract, which is a major part of the digestive system, or in the liver and kidneys was always probable," Ross said. "The detection of microplastics in tissues such as the heart and lungs, however, suggests that the microplastics are going beyond the digestive system and likely undergoing systemic circulation. The brain blood barrier is supposed to be very difficult to permeate. It is a protective mechanism against viruses and bacteria, yet these particles were able to get in there. It was actually deep in the brain tissue."

That brain infiltration also may cause a decrease in glial fibrillary acidic protein (called "GFAP"), a protein that supports many cell processes in the brain, results have shown. "A decrease in GFAP has been associated with early stages of some neurodegenerative diseases, including mouse models of Alzheimer's disease, as well as depression," Ross said. "We were very surprised to see that the microplastics could induce altered GFAP signaling."

She intends to investigate this finding further in future work. "We want to understand how plastics may change the ability for the brain to maintain its homeostasis or how exposure may lead to neurological disorders and diseases, such as Alzheimer's disease," she said.

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Oceans release microplastics into the atmosphere

Tiny plastic particles can be found in the sea air even far from coasts, according to a study recently published in the journal Nature Communications. The microplastics come from partly unexpected sources.

Microplastic particles are present in the marine atmosphere even in remote parts of the world. These tiny particles come from land sources but are also re-emitted into the atmosphere from the sea, a study by a team of German and Norwegian researchers led by Dr Barbara Scholz-Böttcher of the University of Oldenburg has shown. The scientists analysed air samples taken from various sites along the Norwegian coast all the way up to the Arctic region. The results have now been published in the scientific journal Nature Communications.

"With our study, we present data on the mass load of different types of plastic in the marine atmosphere for the first time," said Isabel Goßmann, a doctoral candidate at the University of Oldenburg's Institute for Chemistry and Biology of the Marine Environment (ICBM) and first author of the paper. The research team collected the samples during an expedition with the Research Vessel Heincke in 2021. The northernmost destination was Bear Island, the most southerly island of the Svalbard archipelago which lies halfway between the mainland and the archipelago's largest island, Spitsbergen. The team used two different devices to collect air samples. The devices actively pumped in air and were mounted on the bow of the research vessel at a height of twelve metres.

Different types of plastics identified

The scientists analysed the air samples using pyrolysis-gas chromatography-mass spectrometry. With this method they were able to identify and quantify the different types of plastics in the atmosphere through thermal degradation and selective analysis. They then performed model calculations and reconstructed the sources and distribution paths of the particles, each of which is just a few thousandths of a millimetre in size.

The analysis revealed the omnipresence of polyester particles. Polyethylene terephthalate particles, which presumably entered the atmosphere in the form of textile fibres, were detected in all samples. Other plastic types were also present, including polypropylene polycarbonate and polystyrene. Tire wear particles, the tiny debris abraded from tires during driving and especially braking, were identified as another major source of microplastics. The researchers measured concentrations of up to 37.5 nanograms (one nanogram = one-billionth of a gram) of microplastics per cubic metre of air. "These pollutants are ubiquitous. We find them even in remote polar regions," Goßmann stressed.

Until now, little was known about microplastics pollution levels including tire wear particles in the marine atmosphere. "There are only a handful of studies on the concentration of these pollutants in the air," said team leader Scholz-Böttcher. "Our model calculations indicate that the microplastics in the marine atmosphere come from direct sources on the land as well as from the sea," she added. The team posits that plastic particles floating near the sea surface enter the atmosphere via sea spray and bursting air bubbles produced during stormy weather, for example.

Ships are also a source of microplastics

Microplastics find their way into seawater via rivers, but also through the atmosphere -- particles are washed out of the atmosphere by rain, for example. Another potential source is ship traffic: in an earlier study, a team led by Scholz-Böttcher demonstrated that in the open North Sea, the paint and coatings used on ships is the main source of microplastics. In the current study, chemicals such as polyurethanes and epoxy resins typically used in paints and coatings for ships were also found in the air samples.

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Microplastic pollution: Plants could be the answer

Could plants be the answer to the looming threat of microplastic pollution? Scientists at UBC's BioProducts Institute found that if you add tannins -- natural plant compounds that make your mouth pucker if you bite into an unripe fruit -- to a layer of wood dust, you can create a filter that traps virtually all microplastic particles present in water.

While the experiment remains a lab set-up at this stage, the team is convinced that the solution can be scaled up easily and inexpensively once they find the right industry partner.

Microplastics are tiny pieces of plastic debris resulting from the breakdown of consumer products and industrial waste. Keeping them out of water supplies is a huge challenge, says Dr. Orlando Rojas, the institute's scientific director and the Canada Excellence Research Chair in Forest Bioproducts.

He noted one study which found that virtually all tap water is contaminated by microplastics, and other research which states that more than 10 billion tons of mismanaged plastic waste will be dispersed in the environment by 2025.

"Most solutions proposed so far are costly or difficult to scale up. We're proposing a solution that could potentially be scaled down for home use or scaled up for municipal treatment systems. Our filter, unlike plastic filters, does not contribute to further pollution as it uses renewable and biodegradable materials: tannic acids from plants, bark, wood and leaves, and wood sawdust -- a forestry byproduct that is both widely available and renewable."

Captures a wide variety of plastics

For their study, the team analyzed microparticles released from popular tea bags made of polypropylene. They found that their method (they're calling it "bioCap") trapped from 95.2 per cent to as much as 99.9 per cent of plastic particles in a column of water, depending on plastic type. When tested in mouse models, the process was proved to prevent the accumulation of microplastics in the organs.

Dr. Rojas, a professor in the departments of wood science, chemical and biological engineering, and chemistry at UBC, adds that it's difficult to capture all the different kinds of microplastics in a solution, as they come in different sizes, shapes and electrical charges.

"There are microfibres from clothing, microbeads from cleansers and soaps, and foams and pellets from utensils, containers and packaging. By taking advantage of the different molecular interactions around tannic acids, our bioCap solution was able to remove virtually all of these different microplastic types."

Collaborating on sustainable solutions

The UBC method was developed in collaboration with Dr. Junling Guo, a professor at the Center of Biomass Materials and Nanointerfaces at Sichuan University in China. Marina Mehling (she/her), a PhD student at UBC's department of chemical and biological engineering, and Dr. Tianyu Guo (she/her), a postdoctoral researcher at the BioProducts Institute, also contributed to the work.

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Automated analysis of microplastic concentrations

How high are concentrations of microplastics in the environment, in our drinking water or in foods? Researchers at the Technical University of Munich (TUM) have developed an automated analysis method for the identification and quantification of particles.

Microplastics are everywhere in the environment. The tiny particles, with diameters of less than 5 millimeters, can also absorb and transport contaminants and toxins. “We urgently need analytical techniques to learn about the size, concentration and composition of these particles,” says Dr. Natalia Ivleva at the Chair of Analytical Chemistry and Water Chemistry at TUM. Together with her team, the scientist has developed a new process.

To be able to detect microplastic particles, the researchers had several hurdles to overcome: The first was the problem of low concentrations. River water, for example, contains massive amounts of suspended solids and fine sand, with plastic accounting for less than 1 percent of the particles. These particles must first be isolated before their concentrations and ultimately their chemical composition are determined. Previous methods have relied on the analysis of the residues that are released when the samples are heated. With that approach, however, it is not possible to determine the number, size and shape of the plastic particles.

Plastics can be identified through light scattering

“Our approach is fundamentally different,” says Dr. Ivleva: “It is particle-based. That means that instead of destroying the particles, we analyze them directly.” To do this, the researchers use a method known as Raman microspectroscopy. It works by shining a monochromatic laser source onto a sample and detecting the light scattered by the molecules. Comparing the scattered light against the laser source provides information on the substance under investigation. To analyze plastic particles with a diameter greater than 1 µm (micrometer), they must first be filtered out of the aqueous solution, detected under the microscope and then illuminated with laser light. Because plastics such as polyethylene, polystyrene and polyvinyl chloride scatter the photons in characteristic ways, they each generate signals as unique as a fingerprint.

Automation instead of manual measurements

It took years to develop the tracing process: “When we started, we still had to make manual measurements,” recalls the chemist. “It took us months to investigate a few thousand particles.” In the meantime the team has succeeded in automating the detection of microplastics. A single analysis no longer takes weeks, but only a matter of hours. Although the tiny particles still have to be filtered out of the aqueous solution, followed by placement of the filter under the Raman microspectroscope, all remaining steps are carried out by the software developed by the team. The plastic particles are first localized with a light microscope, photographed and measured, and the particles are distinguished from fibers. The software uses these data to compute the number of particles and fibers and to select the image sections needed for a statistically significant result in the subsequent Raman spectroscopy.

In the next step, the laser is directed onto the sample and the scattering is detected and analyzed. This allows quick and reliable analysis of the number, size, shape and composition of the microplastics. The open-source TUM-Particle Typer 2 software is now available to researchers around the world.

Nanoplastics require special detection processes

To investigate nanoparticles with diameters of less than 1 µm, however, Dr. Ivleva’s team is already working on a modified process. “Nanoparticles like these are difficult or even impossible to discern under a light microscope. To detect them, we first have to carry out size fractionation and then identify them,” explains the researcher.

For this purpose, a field flow fractionation (FFF) system is used. This creates a water flow that captures the particles – depending on their size – and separates them by transporting them at varying speeds. A specially developed device, combined with Raman spectroscopy, permits the chemical characterization of different types of nanoplastics.

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Hotter sand from microplastics could affect sea turtle development

New research from Florida State University published in Frontiers in Marine Science found that extreme concentrations of microplastics could increase the temperature of beach sand enough to threaten the development of incubating sea turtles.

Sea turtles play a vital role in the marine ecosystem, and for these oceangoing reptiles to thrive, they need healthy beaches where their eggs can incubate successfully.

"Sea turtle sex, fitness and hatchling success is influenced by temperature," said lead author Mariana Fuentes, an associate professor in FSU's Department of Earth, Ocean and Atmospheric Science. "Not much is known on how the presence of microplastic affects the thermal profile of sand. Understanding how changes to the environment could affect the temperature of nesting grounds is important for monitoring the future of these keystone species."

Researchers mixed sand from beaches at the FSU Coastal and Marine Laboratory with black and white microplastic. Concentrations of microplastic ranged from 5% to 30% of the total volume of the sediment sample. Then they recorded temperatures from July through September 2018 by burying digital thermometers at the same depth at which loggerhead sea turtles typically lay their eggs.

They found that samples with higher microplastic concentrations had greater increases in temperature, with the sample containing 30% black microplastic pieces having the highest mean difference in temperature. Those samples were 0.58 degrees Celsius warmer than the control group, an increase that could potentially significantly alter sea turtle hatchling sex ratios, physiological performance, and mortality of embryos.

The good news from the study is that the 30% concentration of microplastics in those samples equates to about 9.8 million pieces per cubic meter, a higher concentration than has been currently found on beaches worldwide. Current research has found the highest reported concentrations collected from beaches is about 1.8 million pieces per cubic meter.

But the amount of microplastics at nesting sites has only recently been explored. It could be higher in locations that haven't been studied yet, and demand for plastic is forecast to increase in the future.

At nesting grounds where incubating eggs are near a 29-degree Celsius boundary -- below which most hatchlings are male, and above which most hatchlings are female -- smaller concentrations of plastic could be enough to push the temperature beyond a crucial threshold.

"Sea turtle eggs are sensitive to temperature, and microplastics are another factor adding to the heat they face," Fuentes said. "This study gives us a baseline for future research on how they are affecting the nesting environment."

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