What Is: Microplastics

Microplastic
Credit: Scientific Frontline

The Invisible Tide of Plastic

The modern era has been defined, in part, by the versatility and ubiquity of plastic. Yet, this celebrated 20th-century material has given rise to a paradoxical form of pollution—one so pervasive and minute that its scale was largely unrecognized until recently. Microplastics, the synthetic dust of our industrial age, represent a global environmental challenge of unprecedented complexity. These tiny particles, born from the fragmentation of larger debris and the intentional design of microscopic products, have infiltrated every corner of the planet. Scientific expeditions have confirmed their presence from the summit of Mount Everest to the abyssal depths of the Mariana Trench. More alarmingly, this invisible tide has crossed the final frontier, entering the human body itself, with researchers detecting microplastic particles in human blood, lung tissue, and even the placenta.

The ubiquity of microplastics signals a fundamental disruption of planetary systems. They are not merely inert debris but active agents in the environment, interacting with ecosystems and organisms in complex and often detrimental ways. Their journey spans the globe, carried by ocean currents, river systems, and atmospheric winds, connecting the most remote wilderness to the most densely populated urban centers in a shared system of contamination. This report provides a definitive, evidence-based synthesis of the current scientific understanding of microplastics. It aims to dissect the full scope of this issue, beginning with a fundamental definition of the pollutant and a detailed accounting of its myriad sources. It will then trace the environmental fate and transport of these particles through aquatic, terrestrial, and atmospheric systems. Finally, the report will conduct an exhaustive analysis of their multifaceted impacts on ecological integrity and human health, concluding with a critical evaluation of the policies, technologies, and strategies required to mitigate this pervasive threat.

Turning Plastic Waste into Fuel

Ali Kamali, a doctoral candidate in chemical and biomolecular engineering, inspects a sample of liquid fuel created from plastics.
Photo Credit: Kathy F. Atkinson

Plastics are valued for their durability, but that quality also makes it difficult to break down. Tiny pieces of debris known as microplastics persist in soil, water and air and threaten ecosystems and human health. Traditional recycling reprocesses plastics to make new products, but each time this is done, the material becomes lower in quality due to contamination and degradation of the polymers in plastics. Moreover, recycling alone cannot keep pace with the growing volume of global plastic waste.

Now, a University of Delaware-led research team has developed a new type of catalyst that enhances conversion of plastic waste into liquid fuels more quickly and with fewer undesired byproducts than current methods. Published in the journal Chem Catalysis, the pilot-stage work helps pave the way toward energy-efficient methods for plastic upcycling, reducing plastic pollution and promoting sustainable fuel production.

“Instead of letting plastics pile up as waste, upcycling treats them like solid fuels that can be transformed into useful liquid fuels and chemicals, offering a faster, more efficient and environmentally friendly solution,” said senior author Dongxia Liu, the Robert K. Grasseli Professor of Chemical and Biomolecular Engineering at UD’s College of Engineering.

Microplastics discovered in Antarctica

A view over the Ellsworth Mountains, West Antarctica.
Photo Credit: Steve Gibbs, BAS

Scientists have discovered microplastics in the snow near some of Antarctica’s deep field camps, revealing how far-reaching plastic pollution has become. While not new, it’s the first time these tiny pieces of plastic have been found in remote locations.

The study was conducted at field camps, at Union Glacier and Schanz Glacier (near the Ellsworth Mountains), where researchers were carrying out field work, and the South Pole where the US Antarctic Program has a research station. It is the first time a new and advanced technique has been used to detect microplastics as small as 11 micrometers (about the size of a red blood cell) in the snow in Antarctica. The study is published this week (6 February 2025) in the journal Science of the Total Environment.

The findings surprised the team as microplastics were found at concentrations ranging from 73 to 3,099 particles per liter of snow. Most of these particles (95%) were smaller than 50 micrometers (0.005 cm, the size of most human cells), suggesting previous studies may have underestimated the extent of microplastic pollution in the region due to less sensitive detection methods.

Previous methods involved hand-picking particles and fibers out of samples for laboratory analyses. However, the newer technique involves melting snow through filter paper and scanning this at a high resolution, using infrared spectroscopy, so any plastics above 11 micrometers can be identified.

Tiny plastic particles are found everywhere

The researchers were out in the southern Arctic Ocean on the research vessel Polarstern and took water samples, which they analyzed for the smallest microplastic particles.
Photo Credit: Clara Leistenschneider, University of Basel

Microplastic particles can be found in the most remote ocean regions on earth. In Antarctica, pollution levels are even higher than previously assumed. This is one finding of a recent study involving researchers from the University of Basel.

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.

Thousands of tons of microplastics found in Moreton Bay

Dr Elvis Okoffo has tested samples of mud from Moreton Bay for microplastics.
Photo Credit: Courtesy of University of Queensland

University of Queensland researchers estimate there could be up to 7000 tons of microplastics polluting vital ecosystems in Brisbane’s Moreton Bay.

Dr Elvis Okoffo from UQ’s Queensland Alliance for Environmental Health Sciences said the team measured plastic stored within 50 surface sediment samples collected across Moreton Bay.

“The level of plastic contamination we found is equivalent to three Olympic swimming pools full of plastic or 1.5 million single use plastic bags,” Dr Okoffo said.

“The main types of plastic detected were polyethylene (PE) and polyvinyl chloride (PVC).

“PE is used for single-use items such as plastic food wrapping, bags and bottles and PVC is used in pipes, building materials, electronics, and clothing.

Scientists uncover evidence that microplastics are contaminating archaeological remains

The study identified 16 different microplastic polymer types across both contemporary and archived samples.
PHoto Credit: York Archaeology

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

The study identified 16 different microplastic polymer types across both contemporary and archived samples. Pic credit: York Archaeology

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

Tiny particles

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 millimeter) 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.

There are large accumulations of plastics in the ocean, even outside so-called garbage patch

Neuston net towed on the side of the German RV SONNE, collecting surface-floating plastic samples when crossing the North Pacific Ocean.
Photo Credit: Philipp Klöckner / UFZ

When plastic ends up in the ocean, it gradually weathers and disintegrates into small particles. If marine animals ingest these particles, their health can be severely affected. Large accumulations of plastic can therefore disrupt the biological balance of marine ecosystems. But which areas are particularly affected? In a recent study, a research team from the Helmholtz Centre for Environmental Research (UFZ), in collaboration with the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), has found large quantities of plastic waste and microplastics in a remote marine protected area in the Pacific Ocean. These quantities were similar to those found in one of the world’s largest known garbage patches. The researchers highlight that plastics are distributed much more widely than expected. The entire ocean ecosystem is threatened. They therefore call for the global emissions of plastics into the ocean to be stopped as quickly as possible. The study has been published in Environmental Science & Technology.

Research reveals new insights into marine plastic pollution

Photo Credit: Lucien Wanda

A groundbreaking study led by researchers at the University of Stirling has uncovered the crucial role of bacteria living on plastic debris.

The research also identifies rare and understudied bacteria that could assist in plastic biodegradation, offering new insights for tackling plastic pollution.

Plastic pollution is a worldwide problem, with up to two million tons estimated to enter oceans every year, damaging wildlife and ecosystems.

In a pioneering study, experts at the University of Stirling’s Faculty of Natural Sciences and the University of Mons (Belgium) analyzed the proteins in plastic samples taken from Gullane Beach in Scotland.

Unlike previous studies carried out in warmer climates that focus on the genetic potential of biofilms inhabiting plastics, this research led by Dr Sabine Matallana-Surget took a unique approach by analyzing the proteins expressed by active microorganisms.

Their findings have unveiled a remarkable discovery of enzymes actively engaged in degrading plastic. Moreover, the team has pioneered new methodologies for enhanced predictions in marine microbiology research.

Biodegradable plastics still damaging to fish

Professor Indrawati Oey, of the Department of Food Science, and Dr Bridie Allan, of the Department of Marine Science, hold the biodegradable plastic used in the study and a photo of the mottled triplefin, the species analyzed.
Photo Credit: University of Otago

Biodegradable plastics may not be the solution to plastic pollution many hoped for, with a University of Otago study showing they are still harmful to fish.

Petroleum-derived microplastics are known to impact marine life, but little is known about the impact of biodegradable alternatives.

The study, published in Science of the Total Environment and funded by a University of Otago Research Grant, is the first to assess the impact petroleum-derived plastic and biodegradable plastic have on wild fish.

Lead author Ashleigh Hawke, who completed a Master of Science in Otago’s Department of Marine Science, says petroleum-derived plastic exposure negatively affected the fish’s escape performance, routine swimming, and aerobic metabolism.

Decontamination method zaps pollutants from soil

Yi Cheng (from left), James Tour and Bing Deng
Photo Credit: Gustavo Raskosky/Rice University

Filtration systems are designed to capture multiple harmful substances from water or air simultaneously, but pollutants in soil can only be tackled individually or a few at a time ⎯ at least for now.

A method developed by Rice University scientists and collaborators at the United States Army Engineer Research and Development Center (ERDC) could help turn soil remediation processes from piecemeal to wholesale.

A team of Rice scientists led by chemist James Tour and researchers from the geotechnical structures and environmental engineering branches of the ERDC showed that mixing polluted soil with nontoxic, carbon-rich compounds that propel electrical current, such as biochar, then zapping the mix with short bursts of electricity flushes out both organic pollutants and heavy metals without using water or generating waste.

Pulling carbon dioxide straight from the air

John Hegarty and Ben Shindel with new ions to facilitate carbon capture
Photo Credit: Courtesy of Northwestern University

Even as the world slowly begins to decarbonize industrial processes, achieving lower concentrations of atmospheric carbon requires technologies that remove existing carbon dioxide from the atmosphere — rather than just prevent the creation of it.

Typical carbon capture catches CO2 directly from the source of a carbon-intensive process. Ambient carbon capture, or “direct air capture” (DAC) on the other hand, can take carbon out of typical environmental conditions and serves as one weapon in the battle against climate change, particularly as reliance on fossil fuels begins to decrease and with it, the need for point-of-source carbon capture.

New research from Northwestern University shows a novel approach to capture carbon from ambient environmental conditions that looks at the relationship between water and carbon dioxide in systems to inform the “moisture-swing” technique, which captures CO2 at low humidities and releases it at high humidities. The approach incorporates innovative kinetic methodologies and a diversity of ions, enabling carbon removal from virtually anywhere.

A Novel Technique to Observe Colloidal Particle Degradation in Real Time

Height images of nanoplastics degrading in real time, captured using high-speed atomic force microscopy. The left side shows a particle containing water, and the right side shows a water-free particle.
Image Credit: Daisuke Suzuki from Shinshu University

Researchers develop an innovative approach using atomic force microscopy to shed light on the degradation of colloidal particles

Degradation of colloidal particles is a common occurrence in nature, be it removal of waste products from cells or the natural degradation of polymers, such as plastics, in the environment. Nanoplastics are a major environmental concern, but little is known about how they are created from plastics over time. Researchers from Shinshu University have now developed a novel approach that utilizes high-speed atomic force microscopy to observe, in real time, the course of degradation of colloidal particles.

In the early 2000s, scientists from the UK made a worrisome discovery that the oceans are teeming with small particles of plastic (less than one millimeter in length) due to the continuous degradation of plastic waste. These microscopic particles of plastic have become a major environmental concern. Scientists classify these small particles as either microplastics or nanoplastics based on their size; the latter term is used exclusively for particles smaller than one micrometer.

New study finds that microplastics can help dangerous bacteria survive on beaches

Microplastics on the beach
Photo Credit: Vera Kratochvil

New research from the University of Stirling has found that dangerous bacteria are able to survive the journey from sewage treatment plants to beaches on microplastic pollution.

During their study, scientists from the University’s Faculty of Natural Sciences found drug-resistant bacteria colonizing microplastics on Scottish beaches.  

The findings could have global consequences, with an estimated 2.3 million tons of plastic pollution thought to be floating in the world’s oceans.

Lead researcher Rebecca Metcalf, supervised by Professor Richard Quilliam, conducted her research by subjecting microplastics colonized by bacteria in wastewater to the different environments that they would likely pass through on their way to our beaches. She found that not only could the bacteria such as E. coli survive the entire journey, but that viable bacteria also survived for seven days on the sand. 

Microplastics limit energy production in tiny freshwater species

Paramecium bursaria
Image Credit: Picturepest
(CC BY 2.0)

Microplastic pollution reduces energy production in a microscopic creature found in freshwater worldwide, new research shows.

Paramecium bursaria contain algae that live inside their cells and provide energy by photosynthesis.

A new study, by the University of Exeter, tested whether severe microplastic contamination in the water affected this symbiotic relationship.  

The results showed a 50% decline in net photosynthesis – a major impact on the algae’s ability to produce energy and release oxygen.

“The relationship I examined – known as photosymbiosis – is commonly found both in freshwater and the oceans,” said Dr Ben Makin, lead author and associate researcher at the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall.

“We know climate change can damage photosymbiotic relationships, including in corals (leading to ‘bleaching’ events).

Tracking ocean microplastics from space

Video Credit: University of Michigan

Microplastic pollution can be spotted from space because its traveling companion alters the roughness of the ocean’s surface

New information about an emerging technique that could track microplastics from space has been uncovered by researchers at the University of Michigan. It turns out that satellites are best at spotting soapy or oily residue, and microplastics appear to tag along with that residue.

Microplastics—tiny flecks that can ride ocean currents hundreds or thousands of miles from their point of entry—can harm sea life and marine ecosystems, and they’re extremely difficult to track and clean up. However, a 2021 discovery raised the hope that satellites could offer day-by-day timelines of where microplastics enter the water, how they move and where they tend to collect, for prevention and clean-up efforts.

The team noticed that data recorded by the Cyclone Global Navigation Satellite System (CYGNSS), showed less surface roughness—that is, fewer and smaller waves—in areas of the ocean that contain microplastics, compared to clean areas.

Synthetic fibers discovered in Antarctic samples show the ‘pristine’ continent is now a sink for plastic pollution

As nations prepare to meet in Uruguay to negotiate a new Global Plastics Treaty, a new study has revealed the discovery of synthetic plastic fibers in air, seawater, sediment and sea ice sampled in the Antarctic Weddell Sea. The field research was carried out by scientists from the University of Oxford and Nekton (a not-for-profit research institute) during an expedition to discover Sir Ernest Shackleton’s ship, the Endurance. The results are published in the journal Frontiers in Marine Science.

Fibrous polyesters, primarily from textiles, were found in all samples. The majority of microplastic fibers identified were found in the Antarctic air samples, revealing that Antarctic animals and seabirds could be breathing them.

‘The issue of microplastic fibers is also an airborne problem reaching even the last remaining pristine environments on our planet’, stated co-author Lucy Woodall, a Professor in the University of Oxford’s Department of Biology and Principal Scientist at Nekton. ‘Synthetic fibers are the most prevalent form of microplastic pollution globally and tackling this issue must be at the heart of the Plastic Treaty negotiations.’ Professor Woodall was the first to reveal the prevalence of plastic in the deep sea in 2014.

Viruses can ‘hitchhike’ on microplastics

Photo Credit: Naja Bertolt Jensen

Microplastics are not just tiny particles that can be ingested, they can also carry viruses, a University of Queensland study has revealed.

The study, led by Associate Prof Jianhua Guo and Dr Ji Lu from UQ’s Australian Centre for Water and Environmental Biotechnology (ACWEB), investigated if microplastics have the ability to harbor viruses, including the one found inside E. coli bacteria.

“We often hear about the human and environmental harm caused by microplastics in water, but there is little known about whether the tiny microplastic particles can carry viruses,” Dr Guo said.

“What we found is that viruses can hitchhike on microplastics and prolong their infectivity, which means there could be an increased risk of virus transmission throughout waterways and the environment.”

Dr Lu said they used the E. coli bacteriophage in the study, which is a virus that infects and replicates within the bacteria itself and is not harmful to humans.

How much microplastic do whales eat? Up to 10 million pieces per day

Humpback whales lunge feed in Monterey Bay. New research shows whales are ingesting plastic in larger quantities than previously thought, and nearly all comes from their prey, not from the enormous volumes of seawater the whales gulp when feeding.
Photo Credit: shadowfaxone

Analysis of ocean plastic pollution and whale foraging behavior tracked with noninvasive tags shows whales are ingesting tiny specks of plastic in far bigger quantities than previously thought, and nearly all of it comes from the animals they eat – not the water they gulp.

The largest animals ever known to have lived on Earth ingest the tiniest specks of plastic in colossal amounts, Stanford University scientists have found.

Published in Nature Communications, the study focuses on blue, fin, and humpback whales and their consumption of plastic fragments no bigger than a few grains of sand, which are commonly called microplastics. The authors combined measures of microplastic concentrations up and down the water column off the coast of California with detailed logs of where hundreds of whales carrying tracking devices foraged for food between 2010 and 2019.

They found the whales predominantly feed 50 to 250 meters below the surface, a depth that coincides with the highest concentrations of microplastic in the open ocean. The planet’s biggest creature – the blue whale – ingests the most plastic, at an estimated 10 million pieces per day as it feeds almost exclusively on shrimplike animals called krill.

“They’re lower on the food chain than you might expect by their massive size, which puts them closer to where the plastic is in the water. There’s only one link: The krill eats the plastic, and then the whale eats the krill,” said study co-author Matthew Savoca, a postdoctoral scholar at Hopkins Marine Station, Stanford’s marine laboratory on the Monterey Peninsula.

Monitoring the "journey" of microplastics through the intestine of a living organism

Drosophila melanogaster 
Credit: Universitat Autònoma de Barcelona

A UAB research team has managed to track the behavior of microplastics during their "journey" through the intestinal tract of a living organism and illustrate what happens along the way. The study, carried out on Drosophila melanogaster using electron microscopy equipment developed by the researchers themselves, represents a significant step towards a more precise analysis of the health risks of being exposed to these pollutants.

The behavior of micro and nanoplastics (MNPLs) inside the organism is a question impossible to answer at present in humans, and in vitro models are not useful. Hence, there is a need to look for models that allow us to answer this question. Furthermore, there are limitations in the current methodologies for detecting and quantifying their presence in different human biological samples, which prevents an accurate assessment of the health risk of exposure.

In this context, researchers from the Mutagenesis Research Group of the Universitat Autònoma de Barcelona (UAB) have managed to monitor the tracking of MNPLs in their "journey" from the environment to the interior of a living organism. They have done it by developing tools based on electron microscopy and in larvae of the Drosophila melanogaster fly, a model organism widely used to study biological phenomena and processes.

New study reveals the global impact of debris on marine life

Dr Sarah Gall
Credit: University of Plymouth

Nearly 700 species of marine animal have been recorded as having encountered man-made debris such as plastic and glass, according to the most comprehensive impact study in more than a decade.

Researchers at Plymouth University found evidence of 44,000 animals and organisms becoming entangled in, or swallowing debris, from reports recorded from across the globe.

Plastic accounted for nearly 92 per cent of cases, and 17 per cent of all species involved were found to be threatened or near threatened on the IUCN Red List, including the Hawaiian monk seal, the loggerhead turtle and sooty shearwater.

In a paper, 'The impact of debris on marine life', published in Marine Pollution Bulletin, authors Sarah Gall and Professor Richard Thompson present evidence collated from a wide variety of sources on instances of entanglement, ingestion, physical damage to ecosystems, and rafting, where species are transported by debris.