Tag Archives: microplastics

Microplastics may alter our cell metabolism

A colorized scanning electron micrograph of a macrophage. Credit: NIAIDCC BY 2.0

Larger plastics never completely disintegrate to their constituent parts; they simply become smaller bits of plastic. These microplastics not only course from rivers to ocean but also reside in every ecosystem. They’re in rain. They strangle marine life. They choke mangrove forests. They’re at the tops of mountains and the bottom of the world. Such is the influence of this enduring substance that has revolutionized the human world.

From food to feces, scientists know that humans consume tiny shards of plastic. As these trifling fragments traverse the human gut, they might cruise by as benign sightseers, on their way to excretion. Alternatively, evidence is mounting that they disembark and disturb a delicate balance in the colon—home to trillions of microorganisms. 

“We like to consider microplastics an inert particulate,” said Eliseo Castillo, an immunologist from the University of New Mexico School of Medicine who presented his group’s findings at the Geological Society of America (GSA) 2021 annual meeting. (The presentation was retroactively withdrawn because of nonpayment of the registration fee.) He had previously spoken on the topic in a Society of Toxicology webinar series in April.

However, if these microplastics pierce the three-tiered veneer of the gut’s security—the microbes, mucus, and a single layer of epithelial cells—the invading plastics would encounter the immune system’s sentinels, called macrophages. In a paper published in Cell Biology and Toxicology, Castillo and his colleagues showed how microplastics change macrophages’ energy-generating mechanisms. In his GSA talk, he explored how similar effects could ripple through the protective layers of the gut, weakening the microbiota itself, which serves as the colon’s first line of defense.

Morphing Macrophage Metabolism

“There are thousands of papers on microplastics,” said Castillo, and “a lot of them deal with invertebrate[s].” Curious about how mammals interact with microplastics, his team focused on mice, whose immune systems’ macrophages are similar to our own. These specialized cells stand guard throughout the body, from brain to lungs, skin to gut, ready to respond to any bodily breach. Should an intruder sneak through the colon’s three-layered defense, Castillo explained, “a macrophage will eat it up.”

Castillo and his team added microplastics to mice macrophages, which the shape-shifting immune cells quickly consumed. “After a 3-day period, we noticed microplastics were still in those cells,” he said. Typically, when a macrophage gobbles dead cells and invading microorganisms, it chews up the gunk (a process called phagocytosis) and expels the refuse for either reuse or elimination. However, Castillo said, “these microplastics weren’t being broken down, and the macrophages were still alive.” Moreover, macrophages with microplastics inside changed their metabolism—the biochemical reactions that keep the cell alive and energized.

For most eukaryotes—any organism that keeps DNA enclosed within a cell’s nucleus—a typical metabolic pathway involves converting sugar and oxygen into energy (cellular respiration). However, cells can also switch to a different kind of metabolism that requires no oxygen, said Castillo. In this case, the sugar breaks down in a process called anaerobic (oxygen-free) glycolysis, which produces less energy per sugar molecule than cellular respiration.

Whether a cell uses respiration or glycolysis affects its immune response, said Castillo. Macrophages reliant on glycolysis, including those jailing microplastics, make molecules that promote inflammation, he explained. Moreover, macrophages containing microplastics displayed slower respiration, possibly because of damage.

Spears, Not Spheres

In typical microplastic studies, said Castillo, “we use microspheres.” In the environment, however, microplastics are less likely to manifest as spheres than as fibers that can easily puncture a cell or infiltrate between them, he said.

The colon harbors more microorganisms than any other part of the digestive tract. These microbes—the gut microbiome—break down fibers and produce molecules our bodies use. Many can live only in oxygen-free environments, said Castillo, and are particularly vulnerable to microplastic spears. In an onslaught of oxygen, he said, anaerobic microbes die. Microbial diversity drops, and the gut is no longer healthy.

Chronic Problem, Policy Solution?

On the basis of unpublished work examining mice poop, microplastics in the gut likely won’t lead to rapid inflammation, but chronic exposure could be harmful, said Castillo. “Over time…microplastics can start to harm, or change, the microbiota, which can start to change the single layer of cells and/or the gut immune system, and this could slowly lead to problems,” he said.

The immune system chronically producing inflammation-related molecules could lead to systemic issues, including Alzheimer’s disease, neurodegeneration, and pulmonary disease, said Tzung Hsiai, a bioengineer and cardiologist at the University of California, Los Angeles who was not involved in the study. If the mechanisms underlying these inflammatory responses or disruption of the gut microbiota can be elucidated, he said, such analysis might provide an avenue for policymakers to react to these issues.

Castillo agreed with Hsiai. “I don’t want to scare people, but we do feel it is important to report our findings to the public,” he said. “Maybe this is an environmental issue that Congress can step in and…deal with, as soon as possible.”

This story originally appeared in Eos Magazine and was republished under a CC BY-NC-ND 3.0 license.

We could blast microplastics out of water using loudspeakers, although the tech is still young

Sound can help us deal with the growing issue of microplastics plaguing the world’s oceans, according to new research.

Image via Pixabay.

Microplastics are building up in all layers of the environment, from soils to waterways, even in the atmosphere. Such particles are produced directly by cosmetics, clothing, or industrial processes, or indirectly through the breakdown of larger pieces of plastic.

They’re becoming a genuine environmental concern risking the health of both humans and wildlife. Considerable effort has been put into developing efficient ways of disposing of microplastics, with varying success. Now, new research from the Institut Teknologi Sepuluh Nopember in Surabaya, Indonesia offers an unusual solution to the problem — filtering them out of the water using sound.

Speakers to the rescue

The approach involves using speakers to generate “bulk acoustic waves” (sound waves that propagate throughout the volume of a substance) in order to force microplastic particles in water to separate from the liquid. This allows for the quick and easy removal of the particles through mechanical means, offering a clean and quick method to scrub waters of microplastics.

During lab testing of their technique, the researchers used two speakers to generate acoustic waves through a sample of water laden with microplastic particles that was circulated through a tube. The force of these waves (sounds propagate through physical motions of a material’s particles) created pressure inside the tube, forcing the plastic microparticles to move towards the center of the tube. This tube eventually split into three channels, with the middle one removing the plastic while the other two carried the cleaner water away.

During the testing, the team’s device scrubbed around 150 liters of polluted water an hour. They tested three types of microplastic particles in pure water and seawater. The effectiveness of the rig depended mostly on the type of water that was flowing through it but also varied with the type of plastic it contained. However, the lowest efficiency ratings of the device were slightly above 56% in pure water and 58% in seawater across all types of microplastics used in the trial.

The team explains that this was only a proof-of-concept run. They’re confident that with further tweaking to the frequency of acoustic waves they generate, of the distance between the speakers and the tube, and the water flow through the tube, higher efficiencies can be attained. How much plastic can be removed throughout a cycle of the device directly depends on how much pressure can be generated in the water using the sound waves, and all those elements would affect this parameter.

One potential issue with the technology that may severely limit its applicability in the wild is that many marine species are highly sensitive to sounds in the audible range of frequency — the same range over which the team blasts their speakers. The authors are hard at work finding potential solutions to this problem. In case this can’t be addressed, the technology still holds promise in scrubbing water before it is dumped in waterways. While this won’t help clean the plastic already floating around the oceans, it can at least limit the influx of new microplastics.

“We believe further development is necessary to improve the cleaning rate, the efficiency, and particularly the safety of marine life,” said Dhany Arifianto, Chair of Vibration and Acoustics at Institut Teknologi Sepuluh Nopember Surabaya, lead researcher on the project.

The findings will be presented at the 181st Meeting of the Acoustical Society of America in Seattle, Washington on Dec. 1st.

Airborne microplastics have a growing influence on the climate, but we need more data

Airborne microplastic particles could start having a significant effect on the world’s climate in the future, a new paper reports.

An airborne microplastic sampling station at Kaitorete Spit in Canterbury, New Zealand. Image credits Alex Aves.

New research at the University of Canterbury, New Zealand, found that airborne microplastics reflect part of the sunlight incoming to the Earth’s surface, thus cooling down the climate. For now, this effect is extremely slight. However, as the quantity of microplastics in the air is bound to increase in the coming decades, this effect will grow in magnitude.

Plastmosphere

“Yes, we focussed on airborne microplastics,” Dr. Laura Revell, Senior Lecturer of Environmental Physics at the University of Canterbury and the paper’s corresponding author told ZME Science in an email. “These were first reported in Paris in 2015 and have since been reported in a range of urban and remote regions.”

“However, we believe that microplastics may be co-emitted from the ocean with sea spray, leading to the concept of the ‘plastic cycle’ i.e., microplastics might be carried with the winds over some distance, be deposited to land, get washed into a river, be transported into the ocean, and then re-enter the atmosphere.”

Microplastics are a growing environmental concern. They’re already present in soils, water, air, and their levels are steadily increasing. Some microplastics are produced directly, for items such as cosmetics, while others are the result of plastic items breaking down in landfills.

Due to their small size and weight, such particles can easily be picked up by winds and carried over immense distances. Large cities such as London or Beijing show huge concentrations of such particles, likely due to how much plastic is used within their boundaries.

That being said, we’re just beginning to understand their full impact as airborne contaminants. The present study helps further our understanding in this regard, by uncovering the interaction between these particles and the planet’s climate. According to the authors, this is the first time the direct effects of airborne microplastics on climate has been calculated.

Other airborne solutions (‘aerosols’) are known to have an effect on the Earth’s climate either by scattering or reflecting incoming sunlight back into space, cooling everything down, or by absorbing radiation on certain frequencies, which warms the planet up.

Against that backdrop, the authors set out to determine what effect airborne microplastics have in this regard. They used climate modeling software to determine the radiative effect (i.e., reflective of absorbing) of common airborne microplastic particles. They focused primarily on the lower layers of the atmosphere, where much of the microplastic contamination is located. Overall, they report, these particles scatter solar radiation, which amounts to them having a minor cooling effect on the climate at surface level.

Exactly how much cooling they produce, however, the team can’t say for sure. We simply don’t have enough measurements of the quantity and distribution of microplastics in the atmosphere, nor do we have solid data on their chemical composition and physical properties.

Further muddying the issue is that microplastic particles can also have a warming effect, which may partially or completely counteract the cooling they cause through the scattering of light.

“After we calculated the optical properties of microplastics to understand how they absorb and scatter light, we realised that we would see them absorbing infrared radiation and contributing to the greenhouse effect. That moment was a surprise, as up until then we had been thinking about microplastics as efficient scatterers of solar radiation,” Dr. Revell adds for ZME Science.

This absorption takes place on a frequency interval of infrared light where greenhouse gasses such as CO2 don’t really capture much energy. In other words, these microplastics tap into energy that’s not readily captured by the current drivers of climate warming.

“Microplastics may therefore contribute to greenhouse warming, although in a very small way (since they have such a small abundance in the atmosphere at present),” Dr. Revell adds. “The dominant effect we see in our calculations with respect to interaction with light, [however] is that microplastics scatter solar radiation (leading to a minor cooling influence).”

In closing, she told me that more recent studies on the topic of airborne microplastics are reporting “quite high” concentrations of these particles in certain areas of the world, such as Beijing. Dr. Revell explains that this is likely due to improvements in technology allowing researchers to pick up on particles of much smaller diameters than before — which passed by undetected before. All of this uncertainty in the data obviously does not bode well for our conclusions.

“Our initial estimates of the climate effects of airborne microplastics are just that — estimates — and will no doubt be revised in future as new studies are performed and gaps in our knowledge are filled,” Dr. Revell concluded for ZME Science.

However, one thing we do know for sure is that with plastic pollution on the rise, the effects of microplastics on the climate are only going to become worse. It’s very likely that it already shapes atmospheric heating or cooling on the local level, the authors explain. If steps are not taken to limit the mismanagement of plastic waste, this effect will grow in magnitude and keep influencing the climate for a long period in the future.

The paper “Direct radiative effects of airborne microplastics” has been published in the journal Nature.

Most baby turtles in the oceans have plastic in their guts. ‘It’s an evolutionary trap,’ scientists say

Green turtle (Chelonia Mydas). Credit: Wikimedia Commons.

Plastic pollution is so rampant in the oceans that it has created an “evolutionary trap” for juvenile sea turtles. This was the conclusion of a new study that found plastic in most juvenile turtles they caught along both the Pacific and Indian Ocean coasts of Australia.

The plastic trap

An evolutionary trap occurs when a previously adaptive behavior now has negative effects on the overall survival and reproduction of an organism. This usually happens when a species’ habitat is altered much faster than the organism can adapt. These traps are quite perverse since species are deceived into making poor habitat choices based upon formerly reliable environmental cues — even when higher quality habitat or resources are still available.

For instance, changing land use in an isolated Nevada meadow has driven the extinction — and subsequent recolonization — of a local population of checkerspot butterflies (Euphydryas editha).

In this particular case, newly hatched turtles have adapted to enter the oceanic zone where they travel on currents, feeding and growing to maturity. These habitats are ideal for their development, mainly because that’s where ample food is being funneled straight to their mouths. The problem is that the same currents also carry plastic debris.

“Juvenile turtles have evolved to develop in the open ocean, where predators are relatively scarce,” said Dr. Emily Duncan, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall. “However, our results suggest that this evolved behavior now leads them into a ‘trap’ – bringing them into highly polluted areas such as the Great Pacific Garbage Patch.

“Juvenile sea turtles generally have no specialized diet – they eat anything, and our study suggests this includes plastic,” she added.

Researchers at the University of Exeter in the UK and Murdoch University in Australia looked at how much and what type of plastics are ingested by small juvenile turtles. The study included 121 sea turtles from five of the world’s seven species: green, loggerhead, hawksbill, olive ridley, and flatback.

The results showed that the vast majority of turtles from the Pacific coast had plastic inside them: 86% of loggerheads, 83% of greens, 80% of flatbacks, and 29% of olive ridleys. On the Indian Ocean coast, the proportion of turtles containing plastic was much smaller, but still concerning. There,  28% of flatbacks, 21% of loggerheads, and 9% of green turtles contained plastic.

No plastic was found in hawksbill turtles on either coast, but this is likely due to the very small sample size consisting of only seven hawksbill.

All the animals included in the study were stranded post-hatchlings and bycaught oceanic juveniles from the longline fisheries in the Coral Sea.

Plastics now represent 80% of all marine debris and can be found virtually everywhere, from surface waters to deep-sea sediments. This debris is generally classed as either macroplastics (with a diameter greater than 1mm) and microplastics (smaller than 1mm). But for the purpose of this study, the researchers classed the debris according to color and type (hard plastics, rope, or plastic bags).

The highest number of ingested plastic pieces occurred in green turtles: one animal in the Indian Ocean contained 343 pieces, and one animal in the Pacific Ocean contained 144. 

“Plastic in the Pacific turtles was mostly hard fragments, which could come from a vast range of products used by humans, while Indian Ocean plastics were mostly fibers – possibly from fishing ropes or nets,” says Duncan, who is the lead author of the study.

The most commonly ingested polymers in both oceans were polyethylene and polypropylene. However, these plastics are so widely used in products that it’s impossible to trace the source. As such, there is no viable solution other than stopping plastic pollution as much as possible at its land-based source before it reaches the ocean.

It’s still not clear how the turtle juveniles’ health is affected by ingesting plastic, though scientists suspect it can lead to malnutrition, chemical contamination, and even death from laceration, obstruction, and perforation of the gastrointestinal tract.

“Hatchlings generally contained fragments up to about 5mm to 10mm in length, and particle sizes went up along with the size of the turtles,” Duncan said.

“The next stage of our research is to find out if and how plastic ingestion affects the health and survival of these turtles. This will require close collaboration with researchers and veterinarians around the world,” she added.

The findings were reported in the journal Frontiers in Marine Science.

Mollusks are the most plastic-filled seafood in the world

New research found that marine mollusks such as mussels, oysters, and scallops, contain the highest levels of microplastic contamination of all seafood.

Image credits Pixabay.

The team, led by members from the Hull York Medical School and the University of Hull has analyzed over 50 studies on the topic of microplastic contamination in seafood. These were published between 2014 and 2020 and worked with species ranging from fish to shellfish all around the world.

Food with a little extras

“A critical step in understanding the full impact on human consumption [of plastics] is in first fully establishing what levels of microplastics [MPs] humans are ingesting,” says Evangelos Danopoulos, a postgraduate student at Hull York Medical School and co-author of the paper. “We can start to do this by looking at how much seafood and fish is eaten and measuring the number of MPs in these creatures.”

Microplastics are produced by the breakdown of larger plastic particles as they decompose slowly; some are produced outright, as additives for cleaning or beauty products. Eventually, they make their way into waterways and the ocean through wastewater. Once there, MPs often become ingested by wildlife that confuses it for bits of food. Microplastics resist digestion and build-up in the animals’ bodies.

Whenever we eat seafood, then, we’re also taking in the plastics they ingested over their lifetimes. MP contamination is not limited to seafood, but it is more pronounced here than in any other type of environment. The team found microplastic content ranged between 0-10.5 microplastics per gram (MPs/g) in mollusks, 0.1-8.6 MPs/g in crustaceans, 0-2.9 MPs/g in fish.

“Microplastics have been found in various parts of organisms such as the intestines and the liver,” says Danopoulos. “Seafood species like oysters, mussels, and scallops are consumed whole whereas in larger fish and mammals only parts are consumed. Therefore, understanding the microplastic contamination of specific body parts, and their consumption by humans, is key.”

“No-one yet fully understands the full impact of microplastics on the human body, but early evidence from other studies suggest they do cause harm.”

China, Australia, and Canada are the largest global consumers of mollusks, the team also found, followed by Japan, the US, Europe, and the UK. Those captured off the coasts of Asia tended to see the highest levels of contamination, suggesting these areas are the most heavily polluted with plastics and microplastics.

The findings showcase the sheer extent of the plastic pollution problem facing our planet. Production of such materials is expected to triple by 2060, meaning it will only get worse and worse in the future unless steps are taken soon. For that to happen, however, we need to get a clearer image of the problem, and the team explains that we need standardized methods of measuring microplastic contamination levels, and more on-the-ground data to see how different oceans and waterways are impacted by them.

The paper, “Microplastic contamination of seafood intended for human consumption: a systematic review and meta-analysis” has been published in the journal Environmental Health Perspectives.

No place high enough to hide: microplastics found on Mt. Everest

Tents, made from waterproof acrylic material, at Camp IV/South Col. In the background, climbers make their way to the summit wearing plastic-based waterproof outdoor gear. Credit: Mariusz Potocki/National Geographic.

Microplastics are often associated with ocean pollution, but a new study shows that the tiny plastic fragments are literally everywhere, from sea level to just below the summit of the highest mountain on Earth.

Researchers affiliated with the National Geographic and Rolex Perpetual Planet Everest Expedition analyzed snow and stream samples from Mount Everest, finding the first evidence of microplastic pollution on a mountain.

“I didn’t know what to expect in terms of results, but it really surprised me to find microplastics in every single snow sample I analyzed. Mount Everest is somewhere I have always considered remote and pristine. To know we are polluting near the top of the tallest mountain is a real eye-opener,” Imogen Napper, a National Geographic Explorer and scientist based at the University of Plymouth, said in a press release.

Napper, known to her colleagues as the “plastic detective” for her persistent efforts with which she trails plastic pollution, also said Mt. Everest can be described as “the world’s highest junkyard.”

Expedition members collected samples from Mt. Everest in 2019, which they shipped to Napper’s lab at the University of Plymouth. Her research revealed significant quantities of polyester, acrylic, nylon, and polypropylene fibers. It’s no coincidence that the same materials are embedded in the outdoor clothing climbers use, as well as tents and climbing ropes.

The highest concentration of microplastics was found around Base Camp, an area at the foot of Mt. Everest where trekkers and hikers spend most of their time on their quest to climb the summit. However, microplastics were found all the way up at 8,440 meters (27,560 feet) above sea level, which is just below the summit.

That’s not all that surprising to see. While Mt. Everest was a major challenge to trek, alpine tourism has made the journey much more accessible. Since Edmund Hillary and Tenzing Norgay first reached the highest peak in the world 60 years ago, thousands of climbers have reached the same heights. Every year, hundreds more are added to the list.

Nepalese authorities say that the number of visitors to Sagarmatha National Park, where Everest lies, has roughly tripled in the past 20 years. This increasing number of tourists inevitably comes with a growing amount of rubbish left behind on the mountains.

Now that microplastics have been confirmed on Mt. Everest, the researchers are busy figuring out what’s the best way to clean up this troublesome kind of pollution.

“Currently, environmental efforts tend to focus on reducing, reusing, and recycling larger items of waste. This is important, but we also need to start focusing on deeper technological solutions that focus on microplastics, like changing fabric design and incorporating natural fibers instead of plastic when possible,” Napper says.

“These are the highest microplastics discovered so far,” she added “While it sounds exciting, it means that microplastics have been discovered from the depths of the ocean all the way to the highest mountain on Earth. With microplastics so ubiquitous in our environment, it’s time to focus on informing appropriate environmental solutions. We need to protect and care for our planet.”

The findings appeared in the journal One Earth.

Infant feeding bottles may release millions of microplastics during formula preparation

Credit: Pxfuel.

Most infant feeding bottles on the market across the world are either made of polypropylene or include polypropylene-based accessories. This is one of the most versatile types of plastic, due to its toughness, durability, and low cost. However, a new study found that the combination of hot water and mechanical shaking during the formula preparation process can cause the shedding of 1-16 million plastic microparticles per liter. It’s not clear at the moment if this is any cause of concern as the overall impact of microplastic ingestion on human health is unknown.

Microplastics and minihumans

Microplastics are any pieces of plastic smaller than 5 millimeters. Due to rampant plastic pollution, these tiny fragments are virtually everywhere. According to a 2019 study, every liter of ocean water contains 8,300 microplastics. And since plastic virtually last forever, microplastic accumulation will increase sharply with our consumption of plastic and plastic-wrapped goods.

From the water, the microplastic is ingested by creatures and travels higher up the food chain, eventually ending up in humans. Despite the ubuiquitos nature of these environmental contaminants, little is known about the effects of microplastics in human health.

What’s certain is that it’s everywhere, and microplastics exposure may start from the time we’re babies.

In a new study, researchers at Trinity College Dublin in Dublin, Ireland modeled the potential global exposure of infants to microplatics. The team led by Dunzhu Li mined data on the sales of plastic infant formula bottles, finding that polypropilene bottles account for 82.5% of the global bottle market.

The researchers then purchased ten types of plastic bottles that covered nearly 68% of the global online infant feeding bottle market across 48 countries. They then prepared formula in each bottle using guidelines from the World Health Organization (WHO), which recommends mixing the formula with hot water at a minimum of 70°C in order to reduce bacterial loads. Tests were also performed with fluid at 25°C and 95°C.

Using an optical microscope, the researchers counted the number of particles caught in a filter. This analysis showed that the overall average daily consumption of microplastics by infants per capita was 1,580,000 particles per liter of formula, most of which were smaller than 20 micrometers. This exposure increases proportionately with temperature and varied wildly among the bottles, up to 16.2 million particles per liter.

“We were surprised by the quantity, and the temperature dependant nature of the results. Based on research that has been done previously looking at the degradation of plastics in the environment we had a suspicion that the quantities would be substantial – but I don’t think anyone expected the very high levels that we found,” the authors of the new study told ZME Science in an email.

The researchers, however, stress that parents shouldn’t be alarmed. For now, these findings don’t mean anything from a health standpoint.

“Around the potential health implications – the simple answer is – we just don’t know. This is a new and rapidly evolving area of research and the data on the potential impact on human health is not well developed. The indications from natural habitats, and in particular oceanic environments of microplastic (MP) and the impact on the ecology and health of the species we share the planet with would suggest that we should take steps to remedy MP release. This is an area of research we’re actively pursuing,” researchers said.

“Several studies have indicated that high exposure of Poly Styrene MPs could have an adverse impact on mice’ health. However, there is no data available around the impact of Poly Propylene -MPs on human health. Looking at the fate and transport of microplastics through the body is our next step. We are going to collaborate with colleagues in the areas off immunology and biochemistry to try to figure out the exact consequences, if any, of micro, and also, and very importantly, nanoplastics on the body. “

These findings show that the number of microplastics that infants are exposed to has been greatly underestimated, which should inform manufacturers to improve their standards. Ultimately, this is yet another reason for the removal of microplastics from the environment.

“This study is another piece of the puzzle that illustrates that microplastics problem is likely much bigger than we think. This issue is something we need to start really getting to grips with sooner rather than later,” said Prof. Oliver Jones, Professor of Analytical Chemistry and Associate Dean of Biosciences and Food Technology, RMIT University In Melbourne Australia, who was not involved in the study.

The findings appeared in Nature Food. .

More than 50,000 tonnes of microplastics generated by road traffic end up in the ocean

Credit: Pixabay.

Each day, millions of vehicles release microscopic particles of polymers generated by the friction between tires and the road. Some of these particles are so small and light, they’re easily carried by atmospheric winds across the globe. According to a new study, as much as 52,000 tonnes of road-traffic-sourced microplastics carried by winds settle in the ocean every year, with dire consequences for marine life.

“The reason why we wanted to do research to answer this scientific problem was that, although transport of microplastics (MPs) via runoff and wash-out processes to the marine and/or freshwater ecosystem has been studied extensively, very little is known about how these particles are dispersed in the atmosphere and where they are deposited. This is important due to their health impact in animals and humans, but also due to their affinity to absorb organic compounds and heavy metals increasing their toxicity,” Nikolaos Evangeliou of the Norwegian Institute for Air Research (NILU), lead author of the new study, told ZME Science.

Much talk about the environmental impact of tires is focused on their manufacturing. Typically, tires are derived from ethylene and propylene, for which production generates significant greenhouse gas emissions. At the end of their lifecycle, tires often end up in landfills polluting the environment.

However, tires also produce important pollutants during their operation. Due to their constant wear and tear, tiny particles of rubber, fibers, and other organic and inorganic materials are generated and transported via atmospheric currents far away from their source.

Such particles have been previously detected in highly remote areas of the globe — even as far away as the Arctic, where their deposition can decrease the surface albedo effect and accelerate the melting of ice.

Credit: Nature Communications.

In their new study, Evangeliou and colleagues wanted to quantify just how much of these microplastics circulate through the world’s atmosphere on a yearly basis.

“The biggest surprise when conducting this study, which is actually the biggest challenge for the future, is that lack of atmospheric measurements of MPs. Although there are some, they only present number concentrations and only for particles larger than 20 micrometers, which are less labile and less vulnerable to long-range transport, and hence, they cannot travel to long distances from the main source regions. For the record, here we study particles with a size smaller than 10 micrometers. However, many groups are currently working to solve the problem of proper sampling and analysis of MPs and many methodologies are being tested,” Evangeliou told ZME Science.

The particles targeted in the new study are known as non-exhaust traffic-related particles (NETP). They are released due to mechanical abrasion and corrosion, as well as the resuspension of already deposited particles due to turbulence from traffic (Evangeliou calls this “the grasshopper effect”).

NETPs are not only generated by the wear on tires, but also by wear on the clutch and engine, abrasion of bearings, and corrosion of various vehicle components.

“For the tire wear particles (TWPs), the wearing process depends on the type of tire (i.e. size, tread depth, chemical composition, accumulated mileage, set-up), road surface (i.e. material, porosity, condition, maintenance) and vehicle characteristics (i.e. weight, location of driving wheels, engine power), as well as on vehicle’s state of operation (i.e. speed, acceleration, frequency and extent of braking and cornering),” Evangeliou explained.

“Brake wear particle (BWP) emissions depend on the bulk friction material, on the frequency and severity of braking (driving conditions), while speed, condition and maintenance of the automobile can also be important. Another key factor that affects BWP emissions severely
deals with the environmental conditions during the braking (temperature and environmental compounds present in the road).”

Together, TWPs and BWPs constitute around 1.8% of the total plastic production, according to a 2017 study.

That might not seem like a lot, however, tire wear microplastic emissions alone account for roughly 30% of all microplastic pollution in freshwater and oceanic ecosystems. Most of it is sourced in the eastern US, Northern Europe, and the heavily urbanized areas of Southeast Asia. 

As much as 52,000 tonnes of these microscopic particles smaller than 2.5 microns end up in waterways and the world’s oceans every year, according to the new study published in Nature Communications. An additional 20,000 tonnes of microplastics associated with road and vehicle wear are deposited in remote ice-covered regions of the world, where they drive more melting.

Although PM10 (microplastic particles 10 micrometers in size or smaller) are less susceptible to long-range airborne transport than PM2.5, traffic-related emission generates roughly 10 times more such emissions. PM10 particles tend to stay closer to their source — in most situations, that’s urban environments where they can contribute to adverse health effects, particularly those affecting the lungs like asthma.

The exact impact that traffic-related particle emissions have on the climate is currently unknown, but this is something that may be addressed by research in the future.

In the meantime, this study is a perfect illustration of how very small things can add up to produce a significant impact on the planetary level.

Nanoplastics can contaminate plants, making them smaller, shorter

New research reports that microplastics can and do accumulate in plants. Such findings have implications for ecology as well as food safety.

Image via Pixabay.

Micro- and nanoplastics in water and seafood is a growing concern. They are present in ocean water at very high levels, and we ingest an impressive amount of them every year.

Now, researchers are looking into how these particles behave in terrestrial environments, as well. A new study reports that they can accumulate in plants. This impairs their growth and reduces their nutritional value, the authors explain. Such findings suggest that fruits and vegetables can act as a carrier for microplastics, and point to a possible impact on crop yield as we release more and more plastics.

Plasticrops

“Our findings provide direct evidence that nanoplastics can accumulate in plants, depending on their surface charge,” says Baoshan Xing, a Professor at the University of Massachusetts Amherst and corresponding author of the paper.

“Plant accumulation of nanoplastics can have both direct ecological effects and implications for agricultural sustainability and food safety.”

For the study, the team grew Arabidopsis thaliana (thale cress, a model organism) in plots of soil with nanoplastics. These particles were “fluorescently labeled” to allow tracking. After a seven-week growing period, the team compared the plants’ weights, heights, root growth, and levels of chlorophyll.

The fresh weight of plants grown in soils with nanoplastics were between 41.7% and 51.5% lower and they had shorter roots than the controls, the team explains. Exposure to high concentration of nanoplastics also caused plants to grow “significantly shorter than the control” and those exposed to lower concentrations.

The growing zone of the roots after four days of incubation (with different types and concentrations of plastic particles mixed into their soil).
Image credits Xiao-Dong Sun et al., (2020), Nature.

Particles tended to concentrate in certain tissues, depending on their electrical charge. Negatively-charged ones “were observed frequently in the apoplast and xylem” (both involved in transporting fluids around the plant), while positively-charged ones concentrated in the tips of the roots. The latter, while only present at lower levels, have a higher impact on the plant’s health overall, the team estimates.

“Our experiments have given us evidence of nanoplastics uptake and accumulation in plants in the laboratory at the tissue and molecular level using microscopic, molecular and genetic approaches. We have demonstrated this from root to shoot,” says Xing.

With nanoparticles being present in water, they will inevitably find their way into soils as well, especially in irrigated croplands. Their size and electric charge seem to be the main determining factors of whether they’re absorbed and how much they damage the plant.

The team showed that cress can take in plastic particles of up to 200 nanometers, which is way smaller than most microplastic particles. However, we do have evidence of plastic degrading into ever-smaller bits in water. If they break down similarly on dry land, or if irrigation water is contaminated with nanoplastics, they will contaminate crops as well, leading to reduced yields and food insecurity.

The paper “Differentially charged nanoplastics demonstrate distinct accumulation in Arabidopsis thaliana” has been published in the journal Nature.

Florida’s birds of prey are full of microplastics

A new study from the University of Central Florida (UCF) has found, for the first time, microplastics in terrestrial and aquatic birds of prey in the state.

Image credits Harry Burgess.

Some of the birds in whose digestive systems the team found microplastics include hawks, ospreys, and owls. The accumulation of such material can lead to starvation and poisoning, either of which can be life-threatening. The findings are particularly worrying because birds of prey are critical to a functioning ecosystem, the authors note.

A bird’s gut view

“Birds of prey are top predators in the ecosystem and by changing the population or health status of the top predator, it completely alters all of the animals, organisms and habitats below them on the food web,” says Julia Carlin, the study’s lead author and a graduate of UCF’s Department of Biology.

Microplastics are pieces of plastic that are under 5 mm in length, produced from the breaking down of larger pieces of plastic such as synthetic clothes, or that are purposely-made for use in industry, or for health and beauty products.

Plastic ingestion by wildlife was first noted in the 1960s, the team explains, adding that microplastic ingestion has come under increased scrutiny since 2010. Since then, microplastics have been found in the guts of fish, marine birds, filter-feeding invertebrates such as oysters, and humans.

Birds of prey, however, have not been studied for microplastic ingestion due to their protected status.

For the study, the team worked with the Audubon Center for Birds of Prey in Maitland, Florida where injured raptor birds are nursed back to health. This gave them a unique opportunity to study the stomach contents of 63 birds found across Florida that were dead when they arrived at the center or died 24 hours after they arrived.

Microplastics were found in the digestive systems of all the examined birds, totalling nearly 1,200 pieces of plastic. The most common microplastics found were microfibers (86%), which come from synthetic ropes and fabrics, and can be released into the environment from clothes-washing.

The most common colors seen were blue and clear, which the team says is likely caused by the birds confusing these colors with prey or materials that would be useful for nesting.

As for solutions, the team says removing plastic waste from open landfills (so birds can’t pick them up), retrofitting water treatment installations to capture microplastics, and switching to natural fibers in the clothing industry could all help.

The paper “Microplastic accumulation in the gastrointestinal tracts in birds of prey in central Florida, USA” has been published in the journal Environmental Pollution.

Microplastics are all over the place, even in the sea breeze

Global levels of plastic pollution have been increasing ever since plastic products gained commercial popularity in the 1930s. This has created one of the biggest environmental problems of our time.

Credit Wikipedia Commons

While most research has generally assumed that once plastics enter the ocean they are going to stay there, that’s not necessarily the case. A new study suggests that plastic particles can transfer from seawater to the atmosphere and get carried away by the breeze.

Researchers at the University of Strathclyde and the Observatoire Midi-Pyrénées at the University of Toulouse found fragments of plastics in sea spray, suggesting that they are ejected from the seawater in “bubbles”.

“Sea breeze has traditionally been considered ‘clean air’ but this study shows surprising amounts of microplastic particles being carried by it. It appears that some plastic particles could be leaving the sea and entering the atmosphere,” Steve Allen, who co-led the study, told The Guardian.

The “bubble burst ejection” of particles in sea fog or spray, described by Allen “like soda in a glass when it hits your nose”, is a well-known phenomenon. But the new study is the first to show that microplastics are ejected from the ocean through this mechanism. “The ocean is giving the plastic back to us,” Allen said.

Credit PLOS ONE

Plastic debris, such as plastic bags and bottles, breaks down into smaller microplastic in the sea, often invisible to the eye. The microplastics in sea spray were between 5 and 140 micrometers in size. The researchers estimated that up to 136,000 tons of microplastics could be blown onshore by sea spray every year.

Deonie Allen, the study’s co-research lead, told The Guardian that this was the result of “mismanaged waste that comes from the terrestrial environment”. She said the findings could help answer the question of where “missing” oceanic plastic goes after being dumped into the sea, a mystery scientists have been trying to solve for years.

“The transport mechanism is quite complicated” said Allen. “We know plastic comes out of rivers into the sea. Some goes into gyres, some sinks and goes into the sediment, but the quantity on the sea floor doesn’t match the amount of plastic that would make up this equation. There’s a quantity of missing plastic.”

The researchers captured water droplets from sea spray at Mimizan beach in Aquitaine, on the south-west coast of France using a “cloud catcher” and filters set up on top of a sand dune. They analyzed the water droplets for microplastics, taking samples at various wind directions and speeds.

The marine environment has generally been considered a microplastic sink. Earlier studies have identified plastic moving from cities to rivers, rivers to the sea, and — most recently — atmospheric transport of plastic across terrestrial environments out to sea.

An estimated 8 million tons of plastic enters the sea from land and coasts every year. One study estimates just 240,000 tones floats on the surface, leaving us to wonder where the rest goes. Various plastic ocean transport models have suggested “leaky basins” to explain areas that do not contain the predicted quantities of plastic.

The study was published in the journal PLOS ONE.

That lovely Christmas snow? It probably has microplastics in it

From the waters of Antarctica to the food we eat, microplastics are all over the place, with scientists still trying to understand the consequences they have for the environment and our health.

Microplastics are everywhere, and they’re probably also in the pristine white snow.

Credit Wikipedia Commons

Any piece of plastic under the size of five millimeters (0.2 inches) is considered a microplastic. Microplastics can be produced at that size, or come from the degradation of larger pieces.

They enter ecosystems from different sources such as cosmetics and clothing and even eaten by all of us without being aware of it.

Researchers first believed microplastics were transported mainly by water, but that turned out to not be the case.

A 2017 study showed microplastics are even in our drinking water, with the US having the highest contamination rate. But now it has become clear that they can also be transported by wind, ending up in the snow.

The first studies detailing wind transport appeared earlier this year. In April, a group of researchers from France and Scotland discovered microplastic in the Pyrenees, which had been blown in on the wind from Barcelona. Just a few months later, researchers found them in the snow of the Swiss Alps and the Arctic, likely transported by the wind.

On what was the most recent study, researchers from the Desert Research Institute of Reno also found microplastics in the snow of the Sierra Nevadas mountains in California.

This means there’s plenty of microplastics in the air — enough to be considered a type of air pollution — and yes, that also means there’s probably microplastics in snow.

The researchers that worked on the snow of the Alps and the Artic found an average of 1.760 microplastic particles per liter of snow that had fallen on icebergs between Greenland and Norway. The number was much higher in the European Alps locations, with 24.600 particles per liter on average.

The role of microplastics in the snow hasn’t received much attention from researchers so far. That’s why, for example, Columbia University has created a citizen science project called PlastiX-Snow Citizen Science to collect data on this. They hope to get samples of snow meltwater from people all over the US.

“Despite its importance, little is known about microplastic transport and deposition, especially by snow particles, and most people are not aware of the extent of the problem,” an abstract of their plan reads. “The project aims to fill these research and informational gaps using crowd-sourcing to achieve scientific research outputs”

Plastic pollution is now in the fossil record

Humans have littered the planet with so much plastic that they’ve brought in a new geological era — the Anthropocene. Credit: Pixabay.

If our species ever goes extinct, intrepid alien archeologists will judge our legacy not by our bones but from our plastic litter. According to researchers at the Scripps Institution of Oceanography, plastic is now officially in the fossil record. Their analysis of sediments suggests that plastic deposits have increased exponentially since the end of World War II, doubling every 15 years.

Stone age, iron age… plastic age?

For their study, the researchers drilled sediment core samples dating back to 1834 taken from the Santa Barbara Basin seafloor. This location is ideal for assessing plastic deposits because of the still waters and almost total absence of oxygen.

Each half a centimeter of sediment corresponds to roughly two years of history. Microplastics — which are basically any type of plastic fragment that is less than five millimeters in length — were found in all layers of the core. Most of the fragments were actually clothing fibers, though.

The quantity of microplastics increased rapidly after 1945, coinciding with the post-war boom of plastic production. By 2010, the plastic deposition turned out to be 10 times greater than it was before 1945. The post-war layers also included a greater diversity of plastics including bags, polymer particles, besides fibers.

Previously, scientists have found microplastics in the oceans, in polar ice, and even on some of the most remote islands in the world — in other words, plastic pollution is virtually everywhere. More recently, studies have also reported plastics inside human poop, raising concerns about our consumption of microplastics. According to a recent study that analyzed how much plastic Americans ingest, people gulp between 74,000 to 121,000 particles per year, depending on location, age, and sex.

These findings reinforce the notion that we’ve crossed into a new geological era, the so-called Anthropocene or ‘age of mankind.’ Not only have humans affected the fossil record through plastic pollution, we have also produced nuclear explosions which left behind chemical marks that will be visible for millions of years, and altered the atmosphere and the oceans by burning fossil fuels. Even the bones of the livestock we eat are a sign that we are having a dominant impact on the planet — thereby unleashing a clearly distinguishable and unprecedented period in Earth’s geological history.

“This study shows that our plastic production is being almost perfectly copied in our sedimentary record. Our love of plastic is actually being left behind in our fossil record,” said Scripps microplastics biologist Jennifer Brandon, who is also lead author of the new study which was published in the journal Science Advances.

Magnetic coils, the new way to deal with microplastics

Flowing through rivers and oceans, plastic waste has become an important environmental threat across the globe. Trying to deal with the problem, researchers in Australia developed a way to purge water sources of microplastic without harming microorganisms, using a set of magnets.

Credit: Flickr

 

Microplastics are ubiquitous pollutants. Some are too small to be filtered during industrial water treatment, such as exfoliating beads in cosmetics, while others are produced indirectly when larger debris like soda bottles or tires weather amid sun and sand.

“Microplastics adsorb organic and metal contaminants as they travel through water and release these hazardous substances into aquatic organisms when eaten, causing them to accumulate all the way up the food chain,” said senior author Shaobin Wang, a professor at the University of Adelaide (Australia).

Wang and the research team generated short-lived chemicals, called reactive oxygen species, which trigger chain reactions that chop the polimers (long molecules) that makeup microplastics into tiny and harmless segments that dissolve in water. The study was published in the journal Matter.

The problem was reactive oxygen species are often produced using heavy metals such as iron or cobalt, which are dangerous pollutants in their own right and thus unsuitable in an environmental context. To get around this, they used carbon nanotubes laced with nitrogen to help boost the generation of reactive oxygen species.

“Having magnetic nanotubes is particularly exciting because this makes it easy to collect them from real wastewater streams for repeated use in environmental remediation,” says Xiaoguang Duan, a chemical engineering research fellow at Adelaide who also co-led the project.

The carbon nanotube catalysts removed a significant fraction of microplastics in just eight hours while remaining stable themselves in the harsh oxidative conditions needed for microplastics breakdown. Their coiled shape increased stability and maximized reactive surface area. Chemical by-products of this microplastic decomposition, such as aldehydes and carboxylic acids, aren’t major environmental hazards. The team, for example, found that exposing green algae to water containing microplastic by-products for two weeks didn’t harm the algae’s growth.

The next step of the research will be to ensure that the nano springs work on microplastics of different compositions, shapes, and origins, as all microplastics are chemically different. They also think that the byproducts of microplastic decomposition could be harnessed as an energy source for microorganisms.

“If plastic contaminants can be repurposed as food for algae growth, it will be a triumph for using biotechnology to solve environmental problems in ways that are both green and cost-efficient,” Wang says.

 

Water plastic cup.

Plastic is “everywhere” in the ocean, including its deepest trenches — “There’s no good aspect to this,” researchers say

Plastic fragments have been found in the digestive tracts of animals in the deepest parts of the oceans, a new paper reports. The findings illustrate how incredibly wide humanity’s impact on the planet has become.

Water plastic cup.

Image via Pixabay.

We really do live in a plastic world, as that old song used to go. Humanity produces around 350 million metric tones of plastics each year and, sadly, a large chunk of that is meant to be used and immediately discarded. As such, we’ve managed to build up quite a pile of plastic trash — at least five trillion pieces of it are floating around in the world’s oceans.

Polymer diet

All this plastic eventually finds its way into the bellies of fish and other ocean wildlife. Most studies up to now focused on near-surface plastic contamination in wildlife, and all have found it to be widespread in fish, turtles, whales, and sea birds.

A new study, however, aimed to look at the bottom of the oceans. The team analyzed shrimp from six of the world’s deepest ocean trenches looking for signs of plastic ingestion — and their findings are Not Good. In the Mariana Trench, the deepest spot on Earth, 100% of the studied animals had plastic fibers in their guts, the team reports.

“Half of me was expecting to find something but that is huge,” said lead author Alan Jamieson from Newcastle University’s School of Natural and Environmental Sciences.

Jamieson and his team’s day job is finding new species hidden in the depths. But a decade’s worth of abyssal expeditions left them with a sizeable collection of shrimp specimens from between 6,000-11,000 meters (19,500-36,000 feet) beneath the surface. Curious to know whether plastics sunk down to these animals’ environments, they decided to take a look at the shrimp.

“We are sitting on the deepest dataset in the world, so if we find (plastics) in these, we are done,” Jamieson told AFP.

The team admits they were astonished to see how widespread plastic corruption was at the bottom of the ocean. For example, plastic was found in the digestive systems of animals recovered from the Peru-Chile Trench in the southeast Pacific as well as the Japan Trench — although the two are around 15,000 kilometers (9,300 miles) apart.

“It’s off Japan, off New Zealand, off Peru, and each trench is phenomenally deep,” Jamieson said. “The salient point is that they are consistently found in animals all around the Pacific at extraordinary depths so let’s not waste time. It’s everywhere.”

All in all, 65 of the 90 specimen in the team’s collection (72%) had at least one plastic microparticle in their gut. The team does note that these particles could have been ingested by fish at higher depths and were taken to the bottom of the ocean as the animal died. However, analyses performed on the fibers, most of which seem to be clothing fabrics, showed that they were likely several years old. The team reports that the atomic bonds in the plastic fibers had shifted, unlike what you’d see in a ‘fresh’ plastic mass.

Microplastics are generally dumped directly into the sea, the team writes, via sewers and rivers. They then bunch together into larger bodies and start degrading. As part of this process, bacteria starts moving into the plastic mass’ pores — making it heavier until it eventually sinks. Jamieson puts it more succinctly and in words I wouldn’t be allowed to use, so here’s his take on it:

“So even if not a single fibre were to enter the sea from this point forward, everything that’s in the sea now is going to eventually sink, and once it’s in the deep sea where is the mechanism to get it back?” Jamieson asks.

“We are piling all our crap into the place we know least about.”

Plastic contamination seems to be widespread in the ocean’s deepest areas, and the team cautions that we might unwittingly do a massive amount of damage to bottom-dwellers. In theory, plastics should pass unaffected through an animal’s digestive tract, but the team found they caused blockages in the animals they studied.

“The equivalent would be for you to swallow a 2-metre polypropylene rope and expect that not to have an adverse affect on your health,” Jamieson adds.

“There’s no good aspect to this.”

The paper “Microplastics and synthetic particles ingested by deep-sea amphipods in six of the deepest marine ecosystems on Earth” has been published in the journal Royal Society Open Science.

Microplastics.

Microplastics could break down whole ecosystems — they’re making prey unresponsive to predators

Our microplastics are a much more important factor in the health of the ocean than suspected. And they’re up to no good.

Microplastics.

Microplastics.
Image credits Oregon State University / Flickr.

Researchers at the French National Centre for Scientific Research report that microplastics can disrupt predator-prey relationships in the wild. In a new study, the group describes the impact of microplastic consumption on the common periwinkle (Littorina littorea).

Micropastics, macro effects

Periwinkles are a kind of sea snail. They’re not… particularly exciting. They sit on algae-encrusted rocks all day, munching on the plants. They are, however, considered to be a keystone species — they’re prey for many other species, especially crabs (we also eat them sometimes).

The authors wanted to find out what would happen should these periwinkles dine on algae that have absorbed microplastics. Prior research has shown that algae absorbing such products become enriched in hazardous chemicals and metals. Microplastics are porous and soak up these chemicals as they flute around (we’re dumping those chemicals there, too).

Microplastics.

Microplastic beads. They’re quite porous.
Image credits International Maritime Organization / Flickr.

The team’s hypothesis was that when a periwinkle eats the algae, it is also eating the hazardous materials present in the algae. In order to test if this results in any adverse changes for the snails, the team gathered a few periwinkles and brought them into the lab for testing. They also brought along a few crabs to use as predators.

They report that periwinkles which consumed the toxic materials did not react to the crabs in an expected way. Normally, upon spying the predator, the snails pull into their shells or try to hide in the surrounding environment. Those exposed to the toxic materials did not attempt to avoid capture, however, suggesting that they suffered nerve damage of some sort. This is likely due to the ingestion of heavy metals, the team adds.

They note that the levels of toxicity in the microplastics they used for the study were equivalent to those on a typical beach. The findings are thus broadly applicable in real-world conditions — and they point to major changes in the marine environment due to the microplastics we’ve introduced.

The paper “Microplastic leachates impair behavioural vigilance and predator avoidance in a temperate intertidal gastropod” has been published in the journal Biology Letters.

contact lens.

Contact lenses break down into microplastics — so don’t flush them down!

Just throw them in the trash if you don’t want them on your plate later on.

contact lens.

Contact lenses recovered from treated sewage sludge could harm the environment.
Image credits Charles Rolsky.

Unlike glasses, contact lenses are intended for very short usage periods — most are meant to last a single day. Their disposability may have dire consequences for our oceans, however, according to new research. The paper reports that throwing contact lenses down the drain after use may contribute to microplastic pollution.

The researchers are presenting their results today (Monday 20th August) at the 256th National Meeting & Exposition of the American Chemical Society (ACS) in Boston, Mass.

Break-down lenses

Rolf Halden, Ph.D. and paper lead author, says the work was borne of personal experience.

“I had worn glasses and contact lenses for most of my adult life,” Rolf explains. “But I started to wonder, has anyone done research on what happens to these plastic lenses?”

Rolf’s team — which was already involved in plastic pollution research — couldn’t find a single study detailing what happens to these lenses after use. So they decided to research the topic themselves.

They started with a survey aimed at contact lens wearers in the U.S. It revealed that between 15 to 20% of all users flush the lenses down the sink or toilet after use. Considering that roughly 45 million people in the U.S. alone wear such lenses, that’s a lot of people.

Lenses disposed of in this way end up in wastewater treatment plants — between 6 to 10 metric tons of plastic lenses suffer this fate each year in the U.S. alone, the team estimates. As they tend to be denser than water, these lenses sink. This could ultimately pose a threat to aquatic life, especially bottom feeders that may ingest the contacts.

Direct observation of what happens to these lenses in a wastewater treatment plant was a challenge for several reasons. First off, they’re transparent — making them exceedingly hard to track in wastewater. Secondly, contact lenses are made of a special kind of plastic. Unlike other plastic waste (which is largely composed of polypropylene), contact lenses are usually made from a combination of poly(methylmethacrylate), silicones, and fluoropolymers. This material is much softer and permeable to oxygen. However, its behavior in wastewater and wastewater treatment plants was undocumented.

As part of their research, the team exposed five polymer blends found in the majority of lenses to populations of aerobic and anaerobic microorganisms from wastewater treatment plants. Samples of each polymer were exposed to wastewater for varying lengths of time, and finally performed Raman spectroscopy to analyze the material.

The team concluded that microbes in the wastewater treatment facility actually altered the surface of the contact lenses, weakening the bonds in the plastic polymers.

“We found that there were noticeable changes in the bonds of the contact lenses after long-term treatment with the plant’s microbes,” says coauthor Varun Kelkar.

“When the plastic loses some of its structural strength, it will break down physically. This leads to smaller plastic particles which would ultimately lead to the formation of microplastics.”

Marine animals often mistake microplastics for bits of food. Since plastic isn’t digestible, however, these microplastics have a severe effect on the animals’ digestive systems. Since oceans support complex food chains, microplastics can pass from the small fry to larger fish and eventually end up on your plate (or in your glass). Contact lenses could thus lead to unwanted exposures to plastic contaminants and the pollutants that stick to their surfaces.

This is the first research looking into the effects of contact lenses in wild ecosystems, the team notes. They hope their work will determine industry to at least provide labels on the lenses’ packages describing how to properly dispose of the devices — placing them alongside other solid waste.

“Ultimately, we hope that manufacturers will conduct more research on how the lenses impact aquatic life and how fast the lenses degrade in a marine environment,” Halden confesses.

The findings will be presented at the 256th National Meeting & Exposition of the American Chemical Society. You can watch it live here.

Ice core.

Arctic sea ice chock-full of microplastics, with over 12,000 particles per litre of ice

Arctic sea ice contains ‘record levels’ of microplastics, with concentrations two to three times higher than any recorded in the past.

Ice core.

One of the Arctic sea-ice cores being prepared for a microplastic analysis in a lab.
Image credits Tristan Vankann / Alfred-Wegener-Institut.

Ice cores recovered from across the Arctic Ocean tell a chilling tale — the concentrations of plastic trapped in the ice are two to three times higher than any we’ve ever seen before.

Plastic on the rocks

Microplastics are, perhaps unsurprisingly, tiny pieces of plastic. We use the term to refer to bits under five millimeters in length. They’re generally the result of the gradual breakdown process of larger pieces of plastic waste, but a large number of microplastics reaches the oceans directly from health and beauty products, in water from the washing of synthetic textiles, or from car tire abrasion. All in all, the team found 17 different types of microplastics in the ice, including polyethylene and polypropylene (used in packaging), but also paints, nylon, polyester, and cellulose acetate (used to make cigarette filters).

The problem is that once this ice melts, the plastic will be released into the ocean, ultimately finding its way into the bellies or gills of wild animals. Over half the particles the team found in the ice were small enough to be ingested by sea life, notes lead researcher Ilka Peeken of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany.

“No one can say for certain how harmful these tiny plastic particles are for marine life, or ultimately also for human beings,” she adds.

The team gathered ice cores from five regions across the Arctic Ocean in 2014 and 2015. Microplastics were found in every single core, suggesting that the pollutants are ubiquitous in surface ocean waters, at least in the Arctic.

These samples were taken back to the lab for analysis to determine their origin. The team reports that the waste’s “plastic fingerprint” points to the huge patch of garbage in the Pacific Ocean as the main source. The rest of the microplastics seem to originate from local pollution, most notably from fishing and shipping.

Some of the particles they found were very tiny indeed. The team reports finding microplastics that were as tiny as 11 micrometers across — roughly one-sixth of the diameter of a human hair.

“[The small dimensions] also explains why we found concentrations of over 12,000 particles per litre of sea ice – which is two to three times higher than what we’d found in past measurements,” said co-researcher Gunnar Gerdts, also from the Alfred Wegener Institute.

With climate change turbo-charging the rates at which Arctic sea ice melts, more and more of these plastic microparticles will be released into the ocean.

The paper “Arctic sea ice is an important temporal sink and means of transport for microplastic” has been published in the journal Nature Communications.

Marine debris accumulation locations in the North Pacific Ocean. (NOAA Marine Debris Program)

Containing Asia’s coasts is out best bet for plastic-free ocean

Plastic bags, bottle caps and plastic fibres are among the myriad of micro plastic debris that wash out into the Pacific Ocean. These get ingested by the marine life like fish, mammals and birds which are dying from choking, intestinal blockage and starvation. Moreover, some are toxic pollutants that are absorbed, transported, and consumed in the food chain eventually reaching humans. Containing and eventually pulling out this plastic debris has proven to be a challenge. One proposed solution is to put a network of floating barriers around the ‘Great Pacific Garbage patch’ — an area where currents concentrated a huge mass of microplastics.

Underneath the floating debris in the Pacific Ocean. Credit: NOAA - Marine Debris Program

Underneath the floating debris in the Pacific Ocean. Credit: NOAA – Marine Debris Program

An analysis made by Dr Erik van Sebille and undergraduate physics student Peter Sherman from Imperial College London found that containing the garbage patch is not the most effective solution. The team modeled the movements of the plastics to trace their source. They found a large portion comes from the Asian coasts, particularly China and Indonesia. By placing plastic collectors like those proposed by the The Ocean Cleanup Project around these coasts way more micro debris would be collected. Namely, 31 per cent of microplastic would be removed compared to only 17 percent in the case of placing all collectors inside the patch, the authors report in Environmental Research Letters.

“The Great Pacific garbage patch has a huge mass of microplastics, but the largest flow of plastics is actually off the coasts, where it enters the oceans,” said Sherman.

“It makes sense to remove plastics where they first enter the ocean around dense coastal economic and population centres,” added Dr van Sebille. “It also means you can remove the plastics before they have had a chance to do any harm. Plastics in the patch have travelled a long way and potentially already done a lot of harm.”

The size and mass of the Great Pacific Garbage patch is disputed. As of now, there is no sound estimate — it’s darn big and dangerous that’s for sure.

Marine debris accumulation locations in the North Pacific Ocean. (NOAA Marine Debris Program)

Marine debris accumulation locations in the North Pacific Ocean. (NOAA Marine Debris Program)

For one, you shouldn’t conjure up an image of floating plastic bottles and yogurt cups miles long. These popup for sure, but most of this garbage is actually small bits of plastic (microplastics) that are suspended throughout the water column, like “flecks of pepper floating throughout a bowl of soup,” says NOAA Marine Debris Program’s Carey Morishige.

To gauge efficiency of containment, the researchers also looked for the areas where the microplastics overlapped with phytoplankton rich waters. Phytoplankton are microorganisms that form the base of the marine food pyramid. By placing the collectors at the coasts, the overlap was reduced by 46 per cent versus 14 percent. Previously, Dr van Sebille showed that 90% of seabirds swallow plastics. This makes sense in light of these most recent findings since seabirds linger around coasts where food is plentiful.

“There is a lot of plastic in the patch, but it’s a relative dead zone for life compared with the richness around the coasts,” said Sherman.

“We need to clean up ocean plastics, and ultimately this should be achieved by stopping the source of pollution,” said Sherman. “However, this will not happen overnight, so a temporary solution is needed, and clean-up projects could be it, if they are done well.”