It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
“Sustainable” condenser tumble dryers create hundreds of tonnes of waterborne microfiber pollution
A new study has revealed that drying laundry using a condenser tumble dryer leads to hundreds of tonnes of potentially harmful microfibers being released into waterways and oceans across the UK and Europe.
IMAGE: EXAMINING MICROFIBERS COLLECTED ON THE DRYER LINT FILTERview more
CREDIT: PROCTER & GAMBLE
A new study has revealed that drying laundry using a condenser tumble dryer leads to hundreds of tonnes of potentially harmful microfibers being released into waterways and oceans across the UK and Europe.
Researchers from Northumbria University, worked in partnership with scientists at consumer goods giant Procter and Gamble on the study, which is published today (24 May) in the scientific journal PLOS ONE.
The team found that while condenser dryers may reduce the volume of airborne microfibers being released compared to vented dryers, they are still a significant contributor of waterborne microfiber pollution, with more than 600 tonnes of microfibers being poured down household drains.
Both types of tumble dryer produce microfiber pollution. Although recent studies have suggested that moving from vented tumble dryers to condenser dryers could reduce airborne microfiber pollution, their impact on waterborne microfiber pollution has been unknown until now.
While condenser dryers collect moisture from wet clothes into a container, rather than exhausting microfibers into the air as vented dryers do, the researchers found that condenser dryers in the UK and Europe still produce more than 7,200 tonnes of microfiber annually.
Although 91% of this is collected in the lint filter, which many consumers dispose of in their household waste, the remaining microfibers – a massive 641 tonnes, equivalent to the weight of more than 100 adult male African elephants – are collected in the condenser and poured down the drain. This makes condenser tumble dryers significant sources of microfiber water pollution.
However, some appliance manufacturers suggest that consumers should clean their lint filters under a tap. If consumers follow this guidance, it could lead to ten times more tonnes of microfibers entering our waterways. This means that the drying process is causing more waterborne microfiber pollution than the washing process.
To evaluate the environmental impact of condenser dryers, Professor John Dean, from Northumbria University’s Department of Applied Sciences, worked alongside researchers at Procter & Gamble to test loads of new, clean garments as well as dirty laundry sourced from volunteers in Newcastle upon Tyne. They collected and analysed microfibers from several components of each type of dryer.
“We have for the first time focused on microfiber release from vented and condenser dryers using real consumer laundry loads,” said Professor Dean, an expert in analytical science and environmental pollutants.
“It was found that most microfibers released from dryers is collected in the lint filter, thereby preventing release into the environment. However, when you realise that some manufacturers then recommend regular washing of the lint filter under a running tap, this contributes directly to an increase of waterborne microfibre pollution.
“After considering the environmental impact of current domestic household practices, a simple remedy is proffered. Instead of washing the lint filter under the tap after use in the tumble dryer, simply clean the filter either by hand, a light brush, cloth, or vacuum cleaner, and dispose of the collected fibres, as dry waste, in household waste. This simple and effective procedure can reduce microfibre release from tumble dryers and contribute to the protection of the global natural water environment.”
While extensive research has been carried out into the quantities of microfibers released down the drain by washing machines, historically, less has been understood about the release from tumble dryers.
However, in recent years, the spotlight has shifted from the washing machine to the tumble dryer because fibers also become released from textiles during the drying process.
The team is now urging the appliance industry, its trade associations, and legislators to recognise that all types of tumble dryer can be significant contributors to the problem of environmental microfiber pollution.
The researchers say that efforts are needed to mitigate this issue through revised usage instructions and improved appliance design.
Current plans to introduce microfiber filtration systems into washing machines are expected to reduce the environmental impact of that stage in the laundering process. This study suggests that similar approaches to tumble dryers is a logical next step.
Dr Neil Lant, a Research Fellow at P&G and their leading scientist on this study, added: “The contribution of washing machines to aquatic microfiber pollution has now been extensively studied and filtration technology is now being integrated into those appliances to mitigate the issue.
“Our recent work in collaboration with Northumbria University has recognised, for the first time, that the most important tumble dryer types used in Europe – condenser and heat pump – can also be significant contributors to aquatic microfiber pollution, especially if users wash lint filters in a sink.
“We do over 7 billion dryer loads in the UK and EU each year, with condenser dryers generating 7,200 tonnes of microfibre. We can prevent around 90% of that from causing water pollution by cleaning lint filters into household waste, but to deal with the rest we’ll need to redesign the air filtration systems in all types of dryers.”
Procter & Gamble has been working with analytical and forensic fibre science experts at Northumbria University for over six years to improve our understanding of microfibre release during washing and drying.
Fibers lost during the wear and care of textiles may pose a risk to the environment and human health when released into air and water. A study published in PLOS ONE by Neil J. Lant at Procter & Gamble, Newcastle Innovation Center, Newcastle upon Tyne, United Kingdom and colleagues suggests that while condenser dryers may reduce airborne microfibers compared to vented dryers, they are a significant contributor of waterborne microfiber pollution.
Recent studies have suggested that transitioning from vented tumble dryers to condenser dryers with no exhaust outlet could reduce airborne microfiber pollution. However, their impact on waterborne microfiber pollution is unknown. To evaluate the environmental impact of condenser dryers, researchers tested loads of new, clean garments as well as dirty laundry sourced from volunteers in Newcastle upon Tyne, United Kingdom. They collected and analyzed microfibers from several components of each type of dryer.
The researchers found that both dryer types produced microfiber pollution, including water pollution from rinsing lint traps in the sink. While condenser dryers are ventless and do not exhaust microfibers into the air, the lint filter, condenser, and condensed water are all significant sources of microfiber water pollution.
Future research is needed, however, to replicate the study using a larger sample size, as well as to explore strategies to sequester, dispose of, or eliminate laundry-based microfiber pollution.
According to the authors, “The appliance industry, its trade associations and legislators should recognize that all types of tumble dryer can be significant contributors to the problem of environmental microfiber pollution and begin efforts to mitigate this issue through revised usage instructions and improved appliance design. Current plans to introduce microfiber filtration systems into washing machines are expected to reduce the environmental impact of that stage in the laundering process, suggesting that reapplication of similar approaches to tumble dryers is a logical next step”.
Neil Lant, of Procter & Gamble, adds: “Our recent work in collaboration with Northumbria University has recognized, for the first time, that the most important tumble dryer types used in Europe (condenser and heat pump) can also be significant contributors to aquatic microfiber pollution, especially if users wash lint filters in a sink. We do over 2 billion dryer loads in the UK each year, generating around 2,000 tonnes of microfibre. We can prevent around 90% of that from causing water pollution by cleaning lint filters into household waste, but to deal with the rest we’ll need to redesign the air filtration systems in all types of dryers.
John Dean, of Northumbria University, adds: “By working collaboratively with the Procter & Gamble Newcastle Innovation Centre’s Dr. Neil Lant, and his colleagues, we have for the first time focused on microfibre release from vented and condenser dryers using real consumer laundry loads. It was found that the vast majority of microfibres released from dryers is collected in the lint filter, thereby preventing release into the environment. You realise that some manufacturers, however, then recommend regular washing of the lint filter under a running tap, which contributes directly to an increase of waterborne microfibre pollution. After considering the environmental impact of current domestic household practices, a simple remedy is proffered. Instead of washing the lint filter under the tap after use in the tumble dryer, simply clean the filter either by hand, a light brush, cloth, or vacuum cleaner, and dispose of the collected fibres, as dry waste, in household waste. This simple and effective procedure can reduce microfibre release from tumble dryers and contribute to the protection of the global natural water environment.”
Citation: Cummins AM, Malekpour AK, Smith AJ, Lonsdale S, Dean JR, Lant NJ (2023) Impact of vented and condenser tumble dryers on waterborne and airborne microfiber pollution. PLoS ONE 18(5): e0285548. https://doi.org/10.1371/journal.pone.0285548
Author Countries: UK
Funding: The study was entirely funded by the following three sources: The Worshipful Company of Launderers provided a grant to AMC through the Master (2022) of that institution and its Education Committee. No grant number was provided. The Worshipful Company of Launderers had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. https://www.launderers.co.uk/. Northumbria University funded the study through employment of JRD and SL, and provision of consumables. Only the co-authors affiliated to this institution were involved in study design, data collection and analysis, decision to publish, and preparation of the manuscript. https://www.northumbria.ac.uk/. Procter & Gamble Technical Centres Ltd provided funding in the form of salaries for NJL, AKM and AJS and purchase of appliances and related laboratory consumables. In addition to NJL, AKM and AJS, another member of Procter & Gamble staff contributed to the study as described in the acknowledgements but only these individuals were involved in study design, data collection and analysis, decision to publish, and preparation of the manuscript. Procter & Gamble management gave approval to publish, but this process did not influence the text of the manuscript. https://www.pg.com/.
Impact of vented and condenser tumble dryers on waterborne and airborne microfiber pollution
ARTICLE PUBLICATION DATE
24-May-2023
COI STATEMENT
I have read the journal’s policy and the authors of this manuscript have the following competing interests: NJL, AKM and AJS are employed by Procter & Gamble Technical Centres Ltd, a wholly owned subsidiary of the Procter & Gamble Company. Procter & Gamble is a manufacturer of fabric care products such as laundry detergents, fabric conditioners and dryer sheets. This does not alter our adherence to all PLOS ONE policies on sharing data and materials.
Not so biodegradable: new study finds bio-based plastic and plastic-blend textiles do not biodegrade in the ocean
First-of-its-kind experiment off Scripps Pier finds only natural fibers degrade in the marine environment; plastic fabrics remain intact one year later
IMAGE: CAGE DESIGN USED FOR THE SEA SURFACE EXPERIMENT THAT TOOK PLACE OFF THE ELLEN BROWNING SCRIPPS MEMORIAL PIER AT UC SAN DIEGO'S SCRIPPS INSTITUTION OF OCEANOGRAPHY IN 2019.view more
CREDIT: SARAH-JEANNE ROYER
Plastic pollution is seemingly omnipresent in society, and while plastic bags, cups, and bottles may first come to mind, plastics are also increasingly used to make clothing, rugs, and other textiles.
A new study from UC San Diego’s Scripps Institution of Oceanography, published May 24 in the journal PLOS One, for the first time tracked the ability of natural, synthetic, and blended fabrics to biodegrade directly in the ocean.
Lead author Sarah-Jeanne Royer conducted an experiment off the Ellen Browning Scripps Memorial Pier and found that natural and wood-based cellulose fabrics degraded within a month. Synthetic textiles, including so-called compostable plastic materials like polylactic acid (PLA), and the synthetic portions of textile blends, showed no signs of degradation even after more than a year submerged in the ocean.
“This study shows the need for standardizing tests to see if materials promoted as compostable or biodegradable actually do biodegrade in a natural environment,” said Royer, who performed the research while a postdoctoral scholar in the Dimitri Deheyn laboratory at Scripps Oceanography. Royer currently remains affiliated with Scripps Oceanography as a visiting scholar from HawaiĘ»i Pacific University. “What might biodegrade in an industrial setting does not necessarily biodegrade in the natural environment and can end up as marine and environmental pollutants.”
Startling images of landfills stacked with mountains of thrown away clothing in Chile and Kenya show the global ramifications of fast fashion. An estimated 62 percent of textiles— 68 million tons — are now made from plastic fibers and plastic blends, which can persist in the environment for decades to centuries. Synthetic textiles also create plastic pollution from microfibers shedding during regular wearing and washing. Most washing machines are not designed to filter for microfibers, that then end up in wastewater, and ultimately the ocean.
Bio-based plastics made from renewable natural resources such as cornstarch or sugar cane have been marketed as a potential solution to the plastic problem. PLA is one such polymer in the bio-based plastics market, often labeled as biodegradable and compostable. The team chose this textile for the study given its extensive use as a replacement for oil-based materials.
For the experiment, ten different types of fabrics were used including wood-based cellulose (known commercially as Lyocell, Modal, and Viscose); natural cellulose (organic virgin cotton and non-organic virgin cotton); bio-based plastic (PLA); oil-based plastic (polyethylene terephthalate and polypropylene), and fabric blends of Lyocell mixed with polyester and polypropylene. All these are commonly used in the textile industry. Polyethylene terephthalate is a type of polyester often marketed as a recycled textile. Polypropylene is used in textiles, carpets, geotextiles, packaging materials, and disposable medical textiles such as masks.
The textile samples were placed in flow-through containers deployed both at the sea surface and at the seafloor approximately 10 meters (32 feet) deep. Samples were examined every seven days with images taken, and small pieces removed from duplicate samples for further examination in the lab. This included scanning electron microscopy to examine the fibers at high resolution, and Raman spectroscopy to gain information about the chemical composition and molecular structure of the fibers. The samples were then submerged again, in a process that lasted for 231 days at the sea surface and 196 days at the seafloor.
After the conclusion of the Scripps Pier experiment, the samples were moved to the Experimental Aquarium at Scripps Oceanography, where samples were exposed to controlled conditions of flowing seawater. While the natural, cellulose-based textiles repeatedly disintegrated in 30-35 days, the oil-based and bio-based materials showed no sign of disintegration even after a total of 428 days.
“The natural, cellulose-based materials would disintegrate in about one month, so we would exchange for a new sample after the old one disintegrated,” said Royer. “The natural samples were replicated five times, while the plastic samples remained the same for more than a year.”
Examining the samples via electron microscopy allowed Scripps marine biologist Dimitri Deheyn, senior author of the study, to measure the size and structure of each fiber. The natural fibers became thinner with time, while the diameter of the plastic fibers remained the same showing no sign of biodegradation. Study co-author Francesco Greco performed the Raman spectroscopy analysis at the Department of Geology of Northwest University, China, looking at the structural-chemical degradation of the fibers. Greco, now at the Weizmann Institute of Science, found significant changes in the chemical fingerprint of the cellulose-based materials, while bio- and oil-based plastics remained unchanged.
Fiber blends, which interweave natural fiber strands with bio- or oil-based plastic strands, are often promoted as a more sustainable alternative to textiles made entirely from synthetic plastics. This study showed, however, that only the natural part of the fiber degraded, with the plastic portion of the blend remaining intact.
Additionally, the same type of fabrics were tested in a closed-system bioreactor by an independent company, which replicates a marine environment in an enclosed, indoor system. The bioreactor allowed measurements of the percent of carbon dioxide produced by microbial activity using the fabrics as nutrients, which was thus used as a proxy for measuring biodegradability. The cellulose-based materials showed complete biodegradation within 28 days, whereas the oil-based and bio-based fibers did not show any sign of biodegradation.
Study authors note that the bio-based polylactic plastic, marketed as an ecologically promising material, and the oil-based polyethylene terephthalate and polypropylene, represent an important source of human-caused pollution, and the fate of how these materials act in a natural environment should be further explored.
"This comparative study highlights how crucial our language is around plastics,” said Deheyn. “Indeed, a bioplastic like PLA, commonly assumed to be biodegradable in the environment because it contains the prefix ‘bio,’ is actually nothing like that."
Given these results, Royer and the team hope consumers will become more aware of the power of their own choices
“Consumers who are concerned about microfiber plastic pollution should be mindful of the materials they are buying,” said Royer. “We should all aim to buy fewer garments, opt for high-quality, cellulose-based materials like cotton, merino or wool that will last longer, or look to more circular and sustainable options that repurpose items like clothing swaps and Buy Nothing groups.”
The study was funded by the Biomimicry for Emerging Science and Technology (BEST) Initiative from the Deheyn lab with contributions from Lenzing, The Walter Munk Foundation for the Oceans, and Preserve Calavera. The Raman analysis was supported by the Young Thousand Talents Plan of China.
In addition to Royer, Deheyn and Greco, Michaela Kogler from Lenzing is a co-author of the study.
Deployment of the sea surface experiment that took place off the Ellen Browning Scripps Memorial Pier at UC San Diego's Scripps Institution of Oceanography in 2019.
CREDIT
Dimitri Deheyn
Figure 1 graphic showing disintegration time in days for five selected types of material exposed to coastal waters at the Ellen Browning Scripps Memorial Pier located at UC San Diego's Scripps Institution of Oceanography in La Jolla, California.
CREDIT
Royer, et al.
JOURNAL
PLoS ONE
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Not so biodegradable: polylactic acid and cellulose/plastic blend textiles lack fast biodegradation in marine waters
ARTICLE PUBLICATION DATE
24-May-2023
A popular compostable plastic doesn’t break down in the ocean
“Biodegradable” is a misleading term for plastic substitutes that require heat to break down or industrial compositing conditions
A widely used compostable plastic persists unchanged in marine environments for at least 14 months, according to a new study in the open-access journal PLOS ONE by Sarah-Jeanne Royer and colleagues from Scripps Institution of Oceanography at the University of California, San Diego. The study highlights the distinction between textile materials that can be composted in a controlled, industrial setting (PLA), and the ones that can undergo biodegradation in natural environments (cellulose-based textiles).
The accumulation and persistence of oil-based plastic waste in the ocean is one of the major ecological problems facing marine life. Macroscopic plastic items, such as discarded water bottles, that enter the ocean may persist for decades in their original form; even when they break up into microscopic pieces, called microplastics, they are not biodegraded, but instead remain undigestible pollutants that permeate the oceans.
In recent years, substitutes have been developed to replace oil-based plastics, with the intention of both reducing fossil fuel use in creating plastic goods, and providing a more environmentally benign waste product when the item is discarded, through composting.
One of the most popular substitutes is polylactic acid (PLA), a polymer of lactic acid derived from fermentation of sugars and starches. PLA will break down back into lactic acid at the high temperatures found in very large compost piles; however, it does not do so reliably or quickly in colder conditions.
To examine the fate of PLA in a natural marine environment, the authors submerged samples of PLA, along with samples of oil-based materials, cellulose-based materials, and blend of cellulose-based and oil-based materials, in cages in the coastal waters off La Jolla, California. Samples were examined weekly for evidence of disintegration and returned to the ocean after a few hours.
The authors found that the cellulose-based material degraded quickly, in less than one month. Laboratory chemical analysis confirmed that the cellulose had been largely broken down by biological processes through CO2 production, not simple mechanical wear. In contrast, neither the oil-based plastic, the blend, nor the PLA showed signs of degradation throughout the 14 months of the experiment.
“Our results indicate that compostability does not imply environmental degradation,” Royer said. “Referring to compostable plastics as biodegradable plastics is misleading as it may convey the perception of a material that degrades in the environment. PLA-based plastics must be composted in appropriately controlled facilities in order to achieve their potential as compostable substitutes for oil-based plastics.”
The authors also add: “This work represents one of the few pioneer studies addressing the comparability between the biodegradability of different material types (natural to fully synthetic and bio-based materials) in natural environmental conditions and controlled closed systems. This study shows the need for standardizing tests to see if materials promoted as compostable or biodegradable such as PLA actually do biodegrade in a natural environment. In this case, consumers who are concerned about microfiber plastic pollution should be informed, knowledgeable and mindful of the materials they are buying.”
Citation: Royer S-J, Greco F, Kogler M, Deheyn DD (2023) Not so biodegradable: Polylactic acid and cellulose/plastic blend textiles lack fast biodegradation in marine waters. PLoS ONE 18(5): e0284681. https://doi.org/10.1371/journal.pone.0284681
Author Countries: USA, Israel
Funding: This work is being supported by the Deheyn lab BEST Initiative (Biomimicry for Emerging Science and Technology Initiative), which is a platform for facilitating the interaction between academia and industry for fundamental research on nature-inspired solutions." The funders can contribute to brainstorming about the study design to address specific questions, but have no role in data collection and analysis, and decision to publish. The funders can sometimes (if requested) be involved in brainstorming about interpretation of data outcome, which inherently can contribute to some extent to the preparation of the manuscript. Otherwise, the funders have no role in directing the publication with regards to its presentation, data content and conclusion. As a courtesy and if requested, drafts of the publications can be shared with the funders to show progress in the publishing process. For the Raman analyses, financial support was provided to FG from the Young Thousand Talents Plan of China (Grant Number 41720104002) and the funders in this case had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
IMAGE: CORY´S SHEARWATERS FORAGING SOUTH OF THE ISLAND OF PICO, AZORES ARCHIPELAGO, PORTUGAL. CREDIT: CHRISTOPHER PHAM / PUFFIN CENDRÉ Ă€ LA RECHERCHE DE NOURRITURE AU SUD DE L’ĂŽLE DE PICO, DANS L’ARCHIPEL DES AÇORES, AU PORTUGAL. PHOTO : CHRISTOPHER PHAMview more
CREDIT: CHRISTOPHER PHAM
Scientists have been worried about the potential harms of microplastics for years. These small plastic particles less than 5 mm in length have been found everywhere because of plastic pollution – from the Earth’s deep oceans to remote regions in Antarctica, and even the seafood we eat. But, are microplastics really harmful?
An international team of scientists, including researchers from McGill University, have found evidence that microplastics in the digestive tract of seabirds altered the microbiome of the gut – increasing the presence of pathogens and antibiotic-resistant microbes, while decreasing the beneficial bacteria found in the intestines.
“Our findings reflect the circumstances of animals in the wild. Since humans also uptake microplastics from the environment and through food, this study should act as a warning for us," say the authors.
“The gut microbiome encompasses all the microbes in the gastrointestinal tract, which help control the digestion of food, immune system, central nervous system, and other bodily processes. It’s a key indicator of health and well-being," says Julia Baak, co-author of the study and a PhD Candidate in the Department of Natural Resource Sciences at McGill University.
To gain a better understanding of how species are affected by diets chronically contaminated with microplastics, the scientists examined the gut microbiome of two seabird species, the northern fulmar (Fulmarus glacialis) and the Cory's shearwater (Calonectris borealis) that live mainly on the high seas and feed on marine mollusks, crustaceans, and fish.
“Until now there was little research on whether the amounts of microplastics present in the natural environment have a negative impact on the gut microbial health of affected species,” says Gloria Fackelmann, who conducted the study as part of her doctoral thesis at the Institute of Evolutionary Ecology and Conservation Genomics at Ulm University in Germany.
In studying the seabirds, the researchers discovered that microplastic ingestion changed the microbial communities throughout the gastrointestinal tract of both seabird species. “The more microplastics found in the gut, the fewer commensal bacteria could be detected. Commensal bacteria supply their host with essential nutrients and help defend the host against opportunistic pathogens. Disturbances can impair many health-related processes and may lead to diseases in the host,” says Fackelmann.
According to the researchers, most studies exploring the impact of microplastics on the microbiome are done in labs using very high concentrations of microplastics. “By studying animals in the wild, our research shows that changes in the microbiome can occur at lower concentrations that are already present in the natural environment,” says Fackelmann.
