Tag Archives: plastic nanoparticles

Nanoplastic particles are attracted to each other

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Plastic waste is of rising concern as researchers report finding it in the Arctic (April 5 2022 ScienceDaily news item), as well as, in human blood (March 25, 2022 article by Margaret Osborne for the Smithsonian Magazine).

This post is highlighting research into how a particular form of plastic degrades in the environment, from an April 27, 2022 news item on ScienceDaily,

Polyethylene, a plastic that is both cheap and easy to process, accounts for nearly one-third of the world’s plastic waste. An interdisciplinary team from the University of Bayreuth has investigated the progressive degradation of polyethylene in the environment for the first time. Although the degradation process leads to fragmentation into ever smaller particles, isolated nanoplastic particles are rarely found in the environment. The reason is that such decay products do not like to remain on their own, but rather attach rapidly to larger colloidal systems that occur naturally in the environment. The researchers have now presented their findings in the journal Science of the Total Environment.

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An April 25, 2022 Universität Bayreuth press release (also on EurekAlert but published on April 27, 2022), which originated the news item, gives more detail about the research,

Polyethylene is a plastic that occurs in various molecular structures. Low-density polyethylene (LDPE) is widely used for packaging everyday consumer goods, such as food, and is one of the most common polymers worldwide as a result of increasing demand. Until now, there have only been estimates as to how this widely used plastic degrades after it enters the environment as waste. A research team from the Collaborative Research Centre “Microplastics” at the University of Bayreuth has now systematically investigated this question for the first time. The scientists developed a novel, technically sophisticated experimental set-up for this purpose. This makes it possible to simulate two well-known and environmentally linked processes of plastic degradation independently in the laboratory: 1.) photo-oxidation, in which the long polyethylene chains gradually break down into smaller, more water-soluble molecules when exposed to light, and 2.) increasing fragmentation due to mechanical stress. On this basis, it was possible to gain detailed insights into the complex physical and chemical processes of LDPE degradation.

The final stage of LDPE degradation is of particular interest for studies addressing the potential impact of polyethylene on the environment. What the researchers discovered was that this degradation does not end with the decomposition of the packaging material released into the environment into many micro- and nanoplastic particles, which have a high degree of crystallinity. The reason is that these tiny particles have a strong tendency to aggregate: they attach rapidly to larger colloidal systems consisting of organic or inorganic molecules and are part of the material cycle in the environment. Examples of such colloidal systems include clay minerals, humic acids, polysaccharides, and biological particles from bacteria and fungi. “This process of aggregation prevents individual nanoparticles created by polyethylene degradation from being freely available in the environment and interacting with animals and plants. However, this is not an ‘all clear’ signal. Larger aggregates that participate in the material cycle in the environment and contain nanoplastics do often get ingested by living organisms. That is how nanoplastics can eventually enter the food chain,” says Teresa Menzel, one of the three lead authors of the new study and a doctoral researcher in the field of polymer materials.

To identify the degradation products formed when polyethylene decomposes, the researchers employed a method that has not been widely used in microplastics research: multi-cross-polarization in solid-state NMR spectroscopy. “This method even allows us to quantify the degradation products yielded by photooxidation,” says co-author Anika Mauel, a doctoral researcher in inorganic chemistry.

Bayreuth’s researchers have also discovered that the degradation and decomposition of polyethylene also leads to the formation of peroxides. “Peroxides have long been suspected of being cytotoxic, meaning they have a toxic effect on living cells. That is another way in which LDPE degradation poses a potential threat to natural ecosystems. These interrelationships need to be studied in more detail in the future,” adds co-author Nora Meides, a doctoral researcher in macromolecular chemistry.

The detailed analysis of the chemical and physical processes involved in the degradation of polyethylene would not have been possible without the interdisciplinary networking and coordinated use of state-of-the-art research technologies on the University of Bayreuth’s campus. In particular, these include scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC).

Here’s a link to and a citation for the paper,

Degradation of low-density polyethylene to nanoplastic particles by accelerated weathering by Teresa Menzel Nora Meides, Anika Mauel, Ulrich Mansfeld, Winfried Kretschmer, Meike Kuhn, Eva M.Herzig, Volker Altstädt, Peter Strohrieg, Jürgen Senker, Holger Ruckdäsche. Science of The Total Environment Volume 826, 20 June 2022, 154035 DOI: https://doi.org/10.1016/j.scitotenv.2022.154035

This paper is behind a paywall.

Nanoplastics in the air we breathe

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Most of the research I’ve seen about polluting nanoplastics it concerns the ocean; this time it concerns the air. This research dates from November 2021 but I didn’t stumble across it until this February 2, 2022 article by Talib Visram for Fast Company (Note: Links have been removed),

By some estimates, people have discarded 4,900 million tonnes of plastic have into the environment. Once in nature, that plastic starts to degrade, fragmenting into microplastics about the size of a sesame seed, which are inadvertently ingested by humans and animals through eating them in seafood and drinking them in water. Some reports suggest that we all consume five grams a week–about the weight of a bottle cap.

But, we may be taking more plastics into our systems through our respiratory systems. There’s been less investigation of nanoplastics: particles smaller than microplastics, so small that they can move huge distances in the air and be more easily inhaled into the bloodstream. A new study looks at the travel of those lighter particles, finding them abundant in the atmosphere, and carried, via aerosol transmission, even to remote areas. As far as the scientists know, it’s “the most accurate record of air pollution by nanoplastics ever made.”

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A February 1, 2022 news item on SciTechDaily.com highlights some of the concerns raised by the research,

In a new study, Empa [Swiss Federal Laboratories for Materials Science and Technology] researcher Dominik Brunner, together with colleagues from Utrecht University and the Austrian Central Institute for Meteorology and Geophysics, is investigating how much plastic is trickling down on us from the atmosphere.

According to the study, some nanoplastics travel over 2000 kilometers through the air. According to the figures from the measurements about 43 trillion miniature plastic particles land in Switzerland every year. Researchers still disagree on the exact number. But according to estimates from the study, it could be as much as 3,000 tonnes of nanoplastics that cover Switzerland every year, from the remote Alps to the urban lowlands. These estimates are very high compared to other studies, and more research is needed to verify these numbers.

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A January 25, 2022 EMPA [Swiss Federal Laboratories for Materials Science and Technology] press release by Noé Waldmann, which originated the news item, provides some technical details,

In a large-scale fundraising campaign, popular YouTubers like Mister Beast and Mark Rober are currently trying to rid the oceans of almost 14,000 tonnes of plastic waste. That’s about 0.15 per cent of the amount that ends up in the oceans every year. But it’s not just our waters that are full of plastic. A new study shows that the spread of nanoplastic through the air is a more widespread problem than previously thought.

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Extreme conditions

The scientists studied a small area at an altitude of 3106 meters at the top of the mountain “Hoher Sonnenblick” in the “Hohe Tauern” National Park in Austria. An observatory of the Central Institute for Meteorology and Geodynamics has been located here since 1886. The observatory is run by meteorologist and Arctic researcher Elke Ludewig. Since research began here in the late 19th century, the observatory has only been non-operational on four days. The research station also served as a base for the study on the spread of nanoplastics in remote areas.

Every day, and in all weather conditions, scientists removed a part of the top layer of snow around a marker at 8 AM and carefully stored it. Contamination of the samples by nanoplastics in the air or on the scientists’ clothes was a particular challenge. In the laboratory, the researchers sometimes had to remain motionless when a colleague handled an open sample.

The origin of the tiny particles was traced with the help of European wind and weather data. The researchers could show that the greatest emission of nanoplastics into the atmosphere occurs in densely populated, urban areas. About 30% of the nanoplastic particles measured on the mountain top originate from a radius of 200 kilometers, mainly from cities. However, plastics from the world’s oceans apparently also get into the air via the spray of the waves. Around 10% of the particles measured in the study were blown onto the mountain by wind and weather over 2000 kilometers – some of them from the Atlantic.

Nanoparticles in the bloodstream

It is estimated that more than 8300 million tonnes of plastic have been produced worldwide to date, about 60% of which is now waste. This waste erodes through weathering effects and mechanical abrasion from macro- to micro- and nanoparticles. But discarded plastic is far from the only source. Everyday use of plastic products such as packaging and clothing releases nanoplastics. Particles in this size range are so light that their movement in the air can best be compared to gases.

Besides plastics, there are all kinds of other tiny particles. From Sahara sand to brake pads, the world is buzzing through the air as abrasion. It is as yet unclear whether this kind of air pollution poses a potential health threat to humans. Nanoparticles, unlike microparticles, do not just end up in the stomach. They are sucked deep into the lungs through respiration, where their size may allow them to cross the cell-blood barrier and enter the human bloodstream. Whether this is harmful or even dangerous, however, remains to be researched.

Included here because of its compelling story is Utrecht University’s November 1, 2021 press release conveying the researchers’ excitement, (Note: Links have been removed)

Nanoplastics found in the Alps, transported by air from Frankfurt, Paris and London

A team of researchers have found nanoplastics at the pristine high-altitude Sonnblick Observatory in the Alps. This is the first time that nanoplastics were found in this area. The researchers were originally looking for certain organic particles, but found nanoplastics by chance, discovering a new analysis method for detecting nanoplastics in the process. …

The researchers were looking for organic particles by taking samples of snow or ice, evaporating them, and then burning the residue to detect and analyse the vapours. “Our detection method is a bit like a mechanical nose. And unexpectedly, it smelled burning plastics in our snow samples,” lead researcher Dušan Materić explains. The detector found the smell of several types of plastic, mostly polypropylene (PP) and polyethylene terephthalate (PET).

The detected plastic particles turned out to be less than 200 nm in size, about one hundredth the width of a human hair. That is significantly smaller than plastic particles detected in previous studies. “With this detection method, we are the first group to quantify nanoplastics in the environment,” says Materić. “Since the high Alps are a very remote and pristine area, we were quite shocked and surprised to find such a high concentration of nanoplastics there.” The results suggest that in addition to microplastics, there might be as much nanoplastics present in these remote places.

Transported by air

“We were quite gripped by these findings,” Materić continues. “It’s highly unlikely that these nanoplastics originated from local pristine Alpine areas. So where did they come from? We completely turned around our research project to study this further.”

The researchers found a striking correlation between high concentrations of nanoplastics and winds coming from the direction of major European cities, most notably Frankfurt and the industrial Ruhr area (Germany), but also the Netherlands, Paris, and even London.

“Advanced modelling supported the idea that nanoplastics are indeed transported by air from these urban places,” says Materić. “That’s potentially alarming, because that could mean that there are hotspots of nanoplastics in our cities, and indeed in the very air we’re breathing. We are currently studying this in more detail.” Since working on the current publication, Materić has already received an additional NWO [Dutch Research Council] grant of 50,000 Euros to study the size distribution of nanoplastics in indoor, urban and rural air.

Here’s a link to and a citation for the paper,

Nanoplastics transport to the remote, high-altitude Alps by Dušan Materić,
Elke Ludewig, Dominik Brunner, Thomas Röckmann, Rupert Holzinger. Environmental Pollution Volume 288, 1 November 2021, 117697 DOI: https://doi.org/10.1016/j.envpol.2021.117697

This paper is open access.

Rapid formation of micro- and nanoplastics in the environment

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Image: Nora Meides.

A June 18, 2021 news item on phys.org announces the results of research into how materials made of plastic break down into micro- and nanoplastic particles in the environment,

Most microplastic particles in the environment originate from larger pieces of plastic. In a long-term study, an interdisciplinary research team at the University of Bayreuth has simulated how quickly plastic breaks down into fragments under natural influences. High-tech laboratory tests on polystyrene show two phases of abiotic degradation. To begin with, the stability of the plastic is weakened by photo-oxidation. Then cracks form and more and more and smaller fragments are released into the environment. The study, published in the journal Environmental Science & Technology, allows conclusions to be drawn about other plastics that are common in the environment.

A June 17, 2021 University of Bayreuth press release, which originated the news item, provides more detail,

Polystyrene is an inexpensive plastic that is often used for packaging and thermal insulation, and is therefore particularly common in plastic waste. As part of their long-term study, the Bayreuth researchers for the first time combined analytical investigations, which were also carried out on polystyrene particles at the atomic level, with measurements determining the behaviour of these particles under mechanical stress. On the basis of this, they developed a model for abiotic degradation, i.e. degradation without the influence of living organisms.

“Our study shows that a single microplastic particle with a diameter of 160 micrometres releases about 500 particles in the order of 20 micrometres – i.e. 0.02 millimetres – over the course of one and a half years of being exposed to natural weathering processes in the environment. Over time, these particles in turn break down into smaller and smaller fragments. An ecocorona can form around these tiny particles, possibly facilitating penetration into the cells of living organisms. This was discovered a few months ago by another Bayreuth research group,” says first author Nora Meides, a doctoral student in macromolecular chemistry at the University of Bayreuth.

n the water, the microplastic particles were exposed to two stress factors: intense sunlight and continuous mechanical stress produced by agitation. In the real-world environment, sunlight and mechanical stress are in fact the two main abiotic factors that contribute to the gradual fragmentation of the particles. Irradiation by sunlight triggers oxidation processes on the surface of the particles. This photo-oxidation, in combination with mechanical stress, has significant consequences. The polystyrene chains become ever shorter. Furthermore, they become increasingly polar, i.e. centres of charge are formed in the molecules. In the second phase, the microplastic particles begin to fragment. Here, the particles break down into smaller and smaller micro- and nanoplastic fragments.

“Our research results are a valuable basis for investigating the abiotic degradation of macro- and microplastics in the environment – both on land and at the surface of water – in more detail, using other types of plastic as examples. We were surprised by the speed of fragmentation ourselves, which again shows the potential risks that could emanate from the growing burden of plastics on the environment. Especially larger plastic waste objects, are – when exposed to sunlight and abrasion – a reservoir of constant microplastic input. It is precisely these tiny particles, barely visible to the naked eye, that spread to the remotest ecosystems via various transport routes,” says Teresa Menzel, PhD student in the area of Polymer Engineering.

“The polystyrene investigated in our long-term study has a carbon-chain backbone, just like polyethylene and polypropylene. It is very likely that the two-phase model we have developed on polystyrene can be transferred to these plastics,” adds lead author Prof. Dr. Jürgen Senker, Professor of Inorganic Chemistry, who coordinated the research work. 

The study that has now been published is the result of the close interdisciplinary cooperation of a working group belonging to the DFG Collaborative Research Centre “Microplastics” at the University of Bayreuth. In this team, scientists from macromolecular chemistry, inorganic chemistry, engineering science, and animal ecology are jointly researching the formation and degradation of microplastics. Numerous types of research technology are available on the Bayreuth campus for this purpose, which were used in the long-term study: among others, ¹³C-MAS-NMR spectroscopy, energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and gel permeation chromatography (GPC).

Here’s a link to and a citation for the paper,

Reconstructing the Environmental Degradation of Polystyrene by Accelerated Weathering by Nora Meides, Teresa Menzel, Björn Poetzschner, Martin G. J. Löder, Ulrich Mansfeld, Peter Strohriegl, Volker Altstaedt, and Jürgen Senker. Environ. Sci. Technol. 2021, 55, 12, 7930–7938 DOI: https://doi.org/10.1021/acs.est.0c07718 Publication Date: May 21, 2021 Copyright © 2021 The Authors. Published by American Chemical Society

This paper is behind a paywall.

In six hours billions of plastic nanoparticles accumulate in marine organisms

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For the sake of comparison, I wish they’d thought to include an image of a giant scallop that hadn’t been used in the research (I have an ‘unplastic’ giant scallop image at the end of this posting),

Caption: These are some of the scallops used as part of the current research. Credit: University of Plymouth

But, they did do this,

A scan showing nanoplastic particles accumulated within the scallop’s gills (GI), kidney (K), gonad (GO), intestine (I), hepatopancreas (HP) and muscle (M). Credit: University of Plymouth [downloaded from https://phys.org/news/2018-12-billions-nanoplastics-accumulate-marine-hours.html]

A December 3, 2018 news item on phys.org announces the research,

A ground-breaking study has shown it takes a matter of hours for billions of minute plastic nanoparticles to become embedded throughout the major organs of a marine organism.

The research, led by the University of Plymouth, examined the uptake of nanoparticles by a commercially important mollusc, the great scallop (Pecten maximus).

After six hours exposure in the laboratory, billions of particles measuring 250nm (around 0.00025mm) had accumulated within the scallop’s intestines.

However, considerably more even smaller particles measuring 20nm (0.00002mm) had become dispersed throughout the body including the kidney, gill, muscle and other organs.

A December 3, 2018 University of Plymouth press release (also on EurekAlert), which originated the news item, adds more detail,

The study is the first to quantify the uptake of nanoparticles at predicted environmentally relevant conditions, with previous research having been conducted at far higher concentrations than scientists believe are found in our oceans.

Dr Maya Al Sid Cheikh, Postdoctoral Research Fellow at the University of Plymouth, led the study. She said: “For this experiment, we needed to develop an entirely novel scientific approach. We made nanoparticles of plastic in our laboratories and incorporated a label so that we could trace the particles in the body of the scallop at environmentally relevant concentrations. The results of the study show for the first time that nanoparticles can be rapidly taken up by a marine organism, and that in just a few hours they become distributed across most of the major organs.”

Professor Richard Thompson OBE, Head of the University’s International Marine Litter Research Unit, added: “This is a ground breaking study, in terms of both the scientific approach and the findings. We only exposed the scallops to nanoparticles for a few hours and, despite them being transferred to clean conditions, traces were still present several weeks later. Understanding the dynamics of nanoparticle uptake and release, as well as their distribution in body tissues, is essential if we are to understand any potential effects on organisms. A key next step will be to use this approach to guide research investigating any potential effects of nanoparticles and in particular to consider the consequences of longer term exposures.”

Accepted for publication in the Environmental Science and Technology journal, the study also involved scientists from the Charles River Laboratories in Elphinstone, Scotland; the Institute Maurice la Montagne in Canada; and Heriot-Watt University.

It was conducted as part of RealRiskNano, a £1.1million project funded by the Natural Environment Research Council (NERC). Led by Heriot-Watt and Plymouth, it is exploring the effects which microscopic plastic particles can have on the marine environment.

In this study, the scallops were exposed to quantities of carbon-radiolabeled nanopolystyrene and after six hours, autoradiography was used to show the number of particles present in organs and tissue.

It was also used to demonstrate that the 20nm particles were no longer detectable after 14 days, whereas 250nm particles took 48 days to disappear.

Ted Henry, Professor of Environmental Toxicology at Heriot-Watt University, said: “Understanding whether plastic particles are absorbed across biological membranes and accumulate within internal organs is critical for assessing the risk these particles pose to both organism and human health. The novel use of radiolabelled plastic particles pioneered in Plymouth provides the most compelling evidence to date on the level of absorption of plastic particles in a marine organism.”

Here’s a link to and a citation for the paper,

Uptake, Whole-Body Distribution, and Depuration of Nanoplastics by the Scallop Pecten maximus at Environmentally Realistic Concentrations by Maya Al-Sid-Cheikh, Steve J. Rowland, Karen Stevenson, Claude Rouleau, Theodore B. Henry, and Richard C. Thompson. Environ. Sci. Technol., Article ASAP DOI: 10.1021/acs.est.8b05266 Publication Date (Web): November 20, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

‘Unplastic giant scallop’

The sea scallop (Placopecten magellanicus) has over 100 blue eyes along the edge of its mantle, with which it senses light intensity. This mollusk has the ability to scoot away from potential danger by flapping the two parts of its shell, like a swimming castenet. Credit: Dann Blackwood, USGS – http://www.sanctuaries.nos.noaa.gov/pgallery/pgstellwagen/living/living_17.html Public Domain

Stunning, isn’t it?

Nanoplastics accumulating in marine organisms

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I’m starting to have a collection of postings related to plastic nanoparticles and aquatic life (I have a listing below). The latest originates in Singapore (from a May 31, 2018 news item on ScienceDaily),

Plastic nanoparticles — these are tiny pieces of plastic less than 1 micrometre in size — could potentially contaminate food chains, and ultimately affect human health, according to a recent study by scientists from the National University of Singapore (NUS). They discovered that nanoplastics are easily ingested by marine organisms, and they accumulate in the organisms over time, with a risk of being transferred up the food chain, threatening food safety and posing health risks.

A May 31, 2018 NUS press release (also on EurekAlert), which originated the news item, expands on the theme,

Ocean plastic pollution is a huge and growing global problem. It is estimated that the oceans may already contain over 150 million tonnes of plastic, and each year, about eight million tonnes of plastic will end up in the ocean. Plastics do not degrade easily. In the marine environment, plastics are usually broken down into smaller pieces by the sun, waves, wind and microbial action. These micro- and nanoplastic particles in the water may be ingested by filter-feeding marine organisms such as barnacles, tube worms and sea-squirts.

Using the acorn barnacle Amphibalanus amphitrite as a model organism, the NUS research team demonstrated for the first time that nanoplastics consumed during the larval stage are retained and accumulated inside the barnacle larvae until they reach adulthood.

“We opted to study acorn barnacles as their short life cycle and transparent bodies made it easy to track and visualise the movement of nanoplastics in their bodies within a short span of time,” said Mr Samarth Bhargava, a PhD student from the Department of Chemistry at the NUS Faculty of Science, who is the first author of the research paper.

“Barnacles can be found in all of the world’s oceans. This accumulation of nanoplastics within the barnacles is of concern. Further work is needed to better understand how they may contribute to longer term effects on marine ecosystems,” said Dr Serena Teo, Senior Research Fellow from the Tropical Marine Science Institute at NUS, who co-supervised the research.

Studying the fate of nanoplastics in marine organisms

The NUS research team incubated the barnacle larvae in solutions of their regular feed coupled with plastics that are about 200 nanometres in size with green fluorescent tags. The larvae were exposed to two different treatments: ‘acute’ and ‘chronic’.

Under the ‘acute’ treatment, the barnacle larvae were kept for three hours in a solution that contained 25 times more nanoplastics than current estimates of what is present in the oceans. On the other hand, under the ‘chronic’ treatment, the barnacle larvae were exposed to a solution containing low concentrations of nanoplastics for up to four days.

The larvae were subsequently filtered from the solution, and examined under the microscope. The distribution and movement of the nanoplastics were monitored by examining the fluorescence from the particles present within the larvae over time.

“Our results showed that after exposing the barnacle larvae to nanoplastics in both treatments, the larvae had not only ingested the plastic particles, but the tiny particles were found to be distributed throughout the bodies of the larvae,” said Ms Serina Lee from the Tropical Marine Science Institute at NUS, who is the second author of the paper.

Even though the barnacles’ natural waste removal pathways of moulting and excretion resulted in some removal of the nanoplastics, the team detected the continued presence of nanoplastics inside the barnacles throughout their growth until they reached adulthood.

“Barnacles may be at the lower levels of the food chain, but what they consume will be transferred to the organisms that eat them. In addition, plastics are capable of absorbing pollutants and chemicals from the water. These toxins may be transferred to the organisms if the particles of plastics are consumed, and can cause further damage to marine ecosystems and human health,” said marine biologist Dr Neo Mei Lin from the Tropical Marine Science Institute at NUS, who is one of the authors of the paper.

The team’s research findings were first published online in the journal ACS Sustainable Chemistry & Engineering in March 2018. The study was funded under the Marine Science Research and Development Programme of the National Research Foundation Singapore.

Next steps

The NUS research team seeks to further their understanding of the translocation of nanoparticles within the marine organisms and potential pathways of transfer in the marine ecosystem.

“The life span and fate of plastic waste materials in marine environment is a big concern at the moment owing to the large amounts of plastic waste and its potential impact on marine ecosystem and food security around the world. The team would like to explore such topics in the near future and possibly to come up with pathways to address such problems,” explained Associate Professor Suresh Valiyaveettil from the Department of Chemistry at the NUS Faculty of Science, who co-supervised the research.

The team is currently examining how nanoplastics affect other invertebrate model organisms to understand the impact of plastics on marine ecosystems.

Here’s a link to and a citation for the paper,

Fate of Nanoplastics in Marine Larvae: A Case Study Using Barnacles, Amphibalanus amphitrite by Samarth Bhargava, Serina Siew Chen Lee, Lynette Shu Min Ying, Mei Lin Neo, Serena Lay-Ming Teo, and Suresh Valiyaveettil. ACS Sustainable Chem. Eng., 2018, 6 (5), pp 6932–6940 DOI: 10.1021/acssuschemeng.8b00766 Publication Date (Web): March 21, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Other plastic nanoparticle postings:

While this doesn’t relate directly to aquatic life, the research focuses on how plastic degrades into plastic nanoparticles,

That’s it for now.

Theoretical tool for understanding the fate of nano- and microplastic in rivers

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An Oct. 17, 2016 news item on Nanowerk announced work being accomplished at Wageningen University (Netherlands),

Very tiny plastic particles of micro and nano size are difficult to measure in the environment to assess exposure risks. Researchers of Wageningen University & Research now provide the first mechanistic modelling study on the behaviour and fate of nano- and microplastic in surface waters.

Plastic debris has been detected in the oceans, in soils, sediments and surface waters worldwide. Emissions are expected to increase by an order of magnitude in the coming years. Fragmentation leads to smaller and smaller particles, eventually reaching the submicron scale. At these very small sizes, plastic particles may pose unforeseen risks. Yet they are hard to measure in the environment so that exposure assessments have to rely on modelling.

Wageningen researcher Ellen Besseling: “We already knew that microplastics are transported in rivers and can reach the sediment, potentially affecting aquatic life. Now we have a theoretical tool that helps us to understand why/how this happens and that helps us to explain what we see. This is important in order to design mitigation strategies for plastic debris of all sizes, and to predict emissions of plastics to our oceans.”

An Oct. 17, 2016 Wageningen University & Research press release, which originated the news item, provides more detail,

In their recent pioneering study published in the journal Environmental Pollution, Ellen Besseling and co-workers simulate the concentrations of plastic particles between 100 nm up to 10 mm for the hydrological flow regime of a real river. The model accounted for direct transport of the particles, but also for aggregation of the particles with natural suspended solids, and the transport and settling of the resulting so-called heteroaggregates. The model also accounted for the presence of biofilm on the plastics, and model scenarios were calculated for plastics of different density. “This provides very insightful results on where in the river bed the ‘hot spot’ locations for presence of nano- and microplastic can be expected,” says project leader Prof Bart Koelmans. No earlier models accounted for all of these processes, and some counterintuitive results were obtained. Settling to the sediment for instance, was important for nano- and microplastics smaller than one micrometer due to settling of aggregates, and for plastic particles bigger than fifty micrometer due to direct settling, but much less for sizes in between. This means that these particles are expected to be exported to sea to a larger extent.

Attachment efficiency
A key parameter in the model is the attachment efficiency, which is the chance that a colliding plastic and natural solid particle actually stick together. Because this parameter was not known, literature values were used taking non-polymer nanoparticles as a proxy for microplastic. These values, however, were used in combination with – also for the first time – new measured values for actual nano- and microplastics. These experimental data for aggregation of nano- and microplastic with suspended particles in natural freshwater appeared to fairly agree to the literature data. Whereas these first results are promising, the research team emphasizes that more research is needed to study the aggregation behaviour of nano- an microplastic in fresh and marine waters.

Risk assessment of plastic debris
The problem of plastic debris is high on the agenda of policymakers and the public, and society calls for an assessment of the risks of plastic debris to man and the environment. A risk assessment for nano- and microplastic requires an assessment of exposure, and of the effects caused by plastics, which then can be compared in a characterisation of actual risks for man and the environment. As long as analytical methods to detect plastic particles are still under construction, models provide invaluable tools to assess exposure to plastic of all sizes. Models can also be used to design monitoring networks and optimize sampling strategies by indicating ‘hot spot’ locations based on first principles. At Wageningen University & Research, several projects aim to develop tools for the risk assessment of plastic debris in marine as well as freshwaters, for instance the new STW-project TRAMP.

Here’s a link to and a citation for the paper,

Fate of nano- and microplastic in freshwater systems: A modeling study by Ellen Besseling, Joris T.K. Quik, Muzhi Sun, Albert A. Koelmans. Environmental Pollution http://dx.doi.org/10.1016/j.envpol.2016.10.001 Available online 13 October 2016

This paper is behind a paywall.

Implications of nanoplastic in the aquatic food chain

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As plastic breaks down in the oceans into plastic nanoparticles, they enter the food chain when they are ingested by plankton. Researchers in Sweden have published a study about the process. From a May 23, 2016 news item on ScienceDaily,

Plastic accounts for nearly eighty per cent of all waste found in our oceans, gradually breaking down into smaller and smaller particles. New research from Lund University in Sweden investigates how nanosized plastic particles affect aquatic animals in different parts of the food chain.

“Not very many studies have been done on this topic before. Plastic particles of such a small size are difficult to study,” says Karin Mattsson.

A May 23, 2016 Lund University press release, which originated the news item, provides more detail,

“We tested how polystyrene plastic particles of different sizes, charge and surface affect the zooplankton Daphnia. It turned out that the size of the nanoparticles that were most toxic to the Daphnia in our study was 50 nanometers”, says Karin Mattsson.

Because zooplankton like Daphnia are also food for many other aquatic animals, the researchers wanted to study the effect of plastic particles higher up in the food chain. They found that fish that ate Daphnia containing nanoplastics experienced a change in their predatory behaviour and poor appetite. In several studies, researchers also discovered that the nanoparticles had the ability to cross biological barriers, such as the intestinal wall and brain.

“Although in our study we used much larger amounts of nanoplastic than those present in oceans today, we suspect that plastic particles may be accumulated inside the fish. This means that even low doses could ultimately have a negative effect”, says Karin Mattsson.

Plastic breaks down very slowly in nature, and once the microscopically small plastic particles reach lakes and oceans they are difficult to remove. Plastic particles also bind environmental toxins that can become part of the food chain when consumed accidentally.

“Our research indicates the need for more studies and increased caution in the use of nanoplastics”, she says.

Karin Mattsson is a physicist and her research project was produced in collaboration between the Centre for Environmental and Climate Research, the Division Biochemistry and Structural Biology and the Division of Aquatic Biology at Lund University. Karin Mattsson is also affiliated with NanoLund, where several studies are currently conducted to evaluate the safety of nanoparticles.

Here’s a link to and a citation for a paper published online in 2014 and in print in 2015,

Altered Behavior, Physiology, and Metabolism in Fish Exposed to Polystyrene Nanoparticles by Karin Mattsson, Mikael T. Ekvall, Lars-Anders Hansson, Sara Linse, Anders Malmendal, and Tommy Cedervall. Environ. Sci. Technol., 2015, 49 (1), pp 553–561 DOI: 10.1021/es5053655
Publication Date (Web): November 07, 2014

Copyright © 2014 American Chemical Society

More recently, Karin Mattson has published her PhD thesis on the topic (I believe it is written in Swedish).

What is the effect of nanoscale plastic on marine life?

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A Nov.27, 2015 news item on Nanowerk announces a new UK (United Kingdom) research project designed to answer the question: what impact could nanoscale plastic particles  have on the marine environment?,

As England brings in pricing on plastic carrier bags, and Scotland reveals that similar changes a little over a year ago have reduced the use of such bags by 80%, new research led by Heriot-Watt University in conjunction with Plymouth University will look at the effect which even the most microscopic plastic particles can have on the marine environment.

While images of large ‘islands’ of plastic rubbish or of large marine animals killed or injured by the effects of such discards have brought home some of the obvious negative effects of plastics in the marine environment, it is known that there is more discarded plastic out there than we can account for, and much of it will have degraded into small or even microscopic particles.

It is the effect of these latter, known as nano-plastics, which will be studied under a £1.1m research project, largely funded by NERC [UK Natural Environment Research Council] and run by Heriot-Watt and Plymouth Universities.

A Nov. 25, 2015 Herriot-Watt University press release, which originated the news item, provides more details,

The project, RealRiskNano, will look at the risks these tiny plastic particles pose to the food web including filter-feeding organisms like mussels, clams and sediment dwelling organisms. It will focus on providing information to improve environmental risk assessment for nanoplastics, based on real-world exposure scenarios replicated in the laboratory.

Team leader Dr Theodore Henry, Associate Professor of Toxicology at Heriot-Watt’s School of Life Sciences, said that the study will build on previous research on nano-material toxicology, but will provide information which the earlier studies did not include.

“Pieces of plastic of all sizes have been found in even the most remote marine environments. It’s relatively easy to see some of the results: turtles killed by easting plastic bags which they take for jelly fish, or large marine mammals drowned when caught in discarded ropes and netting.

“But when plastics fragment into microscopic particles, what then? It’s easy to imagine that they simply disappear, but we know that nano-particles pose their own distinct threats purely because of their size. They’re small enough to be transported throughout the environment with unknown effects on organisms including toxicity and interference with processes of the digestive system.

An important component of the project, to be investigated by Dr Tony Gutierrez at Heriot-Watt, will be the study of interactions between microorganisms and the nanoplastics to reveal how these interactions affect their fate and toxicology.

The aim, said Dr Henry, is to provide the information which is needed to effect real change.“We simply don’t know what effects these nano-plastic particles may pose to the marine environment, to filter-feeders and on to fish, and through the RealRiskNano project we aim to provide this urgently needed information to the people whose job it is to assess risk to the marine ecosystem and decide what steps need to be taken to mitigate it.”

You can find the RealRiskNano website here.