Episode 69: Why plant-based materials don’t solve the microfibre problem.




  • Importance of understanding microfibers in textiles
  • Misconceptions about microfibers
  • How microfibers end up in our food, water, and air
  • The role of textiles in microfiber pollution
  • Recent Research on Microfibers
  • The joint study by the Microfibre Consortium and the Department of Forensic Science textile fibres at North Bury University
  • The role of bio-based textile fibres in a circular and sustainable textiles system
  • The Environmental Impact of Microfibers


Belinda Humphrey - Website

Belinda Humphrey - Instagram

Belinda Humphrey - Email

Microfibre Consortium

Department of Forensic Science textile fibres at North Bury University

Episode six - Are Compostable and Biodegradable the same thing?

The role of bio-based textile fibres in a circular and sustainable textiles system

Research tested the effects of microfibres from both polyester and cotton on the behaviour and growth of shrimp and fish


Welcome to the Fashion Unearthed podcast. If you need help navigating the fashion industry sustainably, you have come to the right place. I'm your host Belinda Humphrey and my hope is to simplify the fashion industry so that businesses can make the best decisions for people, planet and product. 

Hello and welcome to episode 69 of the Fashion Unearthed podcast. I hope everyone out there is well. It's still a little bit weird to think how I'm just sitting in my office nattering on about different things by myself, and then people all over the world, just like you, are listening in, and if you have been listening in, or even if this is your first episode and at the end you enjoy it, I would love it if you could leave a quick rating or a review on Apple or Spotify. It really helps to get the podcast out there and into the ears of more people. 

Today I wanted to talk about microfibres. It's such a big topic, one that I might tackle again later, but I just wanted to highlight a few recent research articles to remind everyone, me included, that this space is complex and sometimes on social media things get boiled down into a “this fibre is bad, this is good”. And it's not that simple. As I said, I'm not immune to wanting to simplify things, but I've really made a conscious effort to double down on thinking critically about what people are saying, who they are, who they work for, what research has come up, who's paid for the research. Because getting to the bottom of things is just as hard when you're working in it, and you would know if you've been listening along for a while in this space, that misinformation is a huge problem. 

Firstly, I just wanted to talk about what microfibres are because I feel like there's a little bit of confusion when I see people talking about it on social media, but when someone says microfibres, people automatically picture tiny bits of plastics. But when someone's talking about microfibres, it includes both plastic microfibres shared by synthetic textiles as well as bio-based ones or plant-based ones, which are released from both natural and semisynthetic fibres, such as Visco and Lisle. And these are all released at different stages, including the production phase of materials like dying, and finishing, but also including during wear and tear washing, and from a variety of products including fibres, clothing, wet wipes, and carpets even. Microplastics are kind of a sub-category of microfibres, and it probably comes as no surprise to you that research has shown that microfibres are everywhere. Our food, water, and even the air we breathe as a subset of microplastics, an estimated 35% of all plastics that end up in our oceans come from textile microfibres. 

We know that the ongoing effects of microplastics are bad, but I think when the word microfibres is mentioned and often used interchangeably with microplastics, a lot of the general public would automatically think only of plastic. They wouldn't think to include bio-based fibres or maybe assume that these are not as harmful as plastics. I suspect not many would include an image of a cotton t-shirt in their mind if someone mentioned microfibres in the ocean. 

I was interested to come across a recent joint study by the Microfibre Consortium and the Department of Forensic Science textile fibres at North Bury University, suggesting that the past assumptions about microfibre pollution, specifically the downplaying of bio-based fibres may need to be re-examined. They conducted research off the eastern coast of Africa and found that natural textile fibres were more prevalent than synthetic alternatives in samples of seawater. In the samples taken along the coast of Kenya and Tanzania, researchers found 2,403 textile fibres, of which 55% were of natural origin, 37% were synthetic and 8% were regenerated cellulose, six viscose or rayon, which when I read it, I had to do a double take. It seems every article I read or person I see on social media is talking about the problem of microfibres being all about plastics. These are the bad guys. Everything else natural such as cotton, linen and wool, all biodegrade. They don't seem to be included in this conversation about the problem of microfibres. 

Now, if you've listened to episode six where I talk about the difference between biodegradable and compostable, you would know that even compostable items need the right environment to break down, and they usually don't if they're in a landfill as there isn't enough air and the temperatures might not be right. I wasn't really convinced that simply switching to natural fibres was the perfect solution. But I was surprised because according to the textile exchange, 62% of fibres in 2020 were synthetics. You'd think that if you were to collect fibres, the majority would be synthetics, which is not what this research showed. Now, obviously, there are other industries that contribute to microfibre production, but you would still think it would kind of be in the ballpark, not the complete opposite.

I did a bit more digging and I came across another report called The role of bio-based textile fibres in a circular and sustainable textiles system. Now, I'll link to all of these in the show notes on the website in the podcast section so you can read them for yourself. But that particular study also drew on a number of studies going back to 2015, demonstrating that 60 to 80% of textile microfibres in both the environment and organisms are not plastic. They go on to say that due to characterization difficulties, some of the natural microfibres were considered microplastics by hundreds of studies leading to disproportionately high microplastic counts and underrepresentation of bio-based microfibres. They say that the environmental threats associated with bio-based microfibres are also underestimated as there's a general assumption that their biodegradability reduces their impact, which if we go back to that earlier study, shows that they're not biodegrading. And finally, they reiterate that the biodegradability and environmental compatibility of bio-based microfibres are strongly affected by processing procedures such as dying coating and other fabric treatments that, for example, increase durability and that the persistence of microfibres in the environment poses risks to human health as they can bioaccumulate when ingested by organisms and lead to the introduction into the human food chain. 

You can kind of see a picture building where I guess the common stories that we're told about natural fibres biodegrading may not be the case, and even if they do, sometimes we're not really sure if of what kind of chemicals have been used in the processing stage as well. Both bio-based and synthetic fibres are making their way into animals and into the food chain. 

Another study that came across revealed the presence of natural and synthetic fibres in the diet of king penguins foraging in South Georgia. 77% of the birds, 36 out of 47 studied, had fecal samples containing microfibres, and most of those microfibres, 88% were of natural origin. Cellulose, cotton, and wool with only 12% being synthetic polyester nylon or semi-synthetics. Now, of course, we don't know how those fibres were dyed what chemicals were applied and the finishing processes, but penguins shouldn't be eating any of this, and it shows that all fibres have the potential to be ingested. If cotton or linens or viscose are dyed or finished with toxic chemicals, they have the potential to be just as harmful as plastics. 

Finally, on the topic of microfibres being ingested, I wanted to mention another study, not to depress you, but to highlight the fact that this space is complex and it needs deeper holistic thinking, not a 32nd clip on social media. It's not black and white or good versus bad. The next piece of research tested the effects of microfibres from both polyester and cotton on the behaviour and growth of shrimp and fish. They found that microfibres from synthetic materials as well as cotton impacted the behaviour and growth of water organisms. Essentially, they measured the impact of microfibre samples of different sizes of ropes made of cotton, polyester, and polypropylene on the growth and development of wild organisms such as rockfish and zooplankton. They measured behavioural responses, growth and ingestion levels in larval and juvenile inland silverside and mice and shrimp, after exposing them to the three microfibre types at three concentrations and different levels of salinity meant to mimic conditions in an estuary which are bodies of water usually found where rivers meet the sea. They found that cotton had no effect on growth in silversides, but did reduce growth in the shrimp at the two lower salinities or salt levels. 

They found synthetic fibres reduced growth in both organisms over just a few days of exposure with polyester and polypropylene having more of an effect on behaviour than cotton did in both organisms. Cotton was not detected in the digestive tracks of silversides, however, polyester and polypropylene were. They were found in the silverside's stomach and gut lining. None of the fibre types was detected in the shrimps. In terms of organism behaviour, cotton impacted both organisms' behaviour more at higher salinities, and polyester and polypropylene had more behavioural impacts at lower salinities. It also mentions cotton and other natural fibres as having a higher propensity for shedding compared to synthetics and their fate and role in the aquatic ecosystems due to different chemical dyes and functional and often toxic finishes is unknown and they may provide more surface area to absorb contaminants. 

We're really seeing the research show that natural fibres don't biodegrade, and in some cases, they're more prevalent than synthetics and they can have an effect on organisms. Knowing that many plant-based or bio-based fabrics could be exposed to chemicals through the processing stage is something that needs to be considered. The degree of effect is still being researched, but I think we can agree that whatever a microfibre is made of, no personal animal should be ingesting it, and I'm pretty sure there are not many benefits associated with doing so. 

I hope that's made you think a little bit more about microfibres and maybe broaden some of the concepts and things that need to be considered as well as understanding that not all microfibres are plastic. The idea that the problem will be solved by natural fibres and they are completely safe also needs to be researched more, and businesses should keep that in mind when they're talking about the benefits of a particular material. 

Again, I'd love it if you had five seconds to give a rating or a bit more time to leave a review on the podcast either on Apple or Spotify. And I'd love to know if today's episode surprised you. You can send me an email at info@belindahumphrey.com or DM or message me on Instagram at @belindahumphrey_, and as always, you'll find the show notes and all the links to the research articles I've mentioned on the website in the podcast section. Thanks so much for listening. See you next time.

Thanks for listening to the Fashion Unearthed podcast. If you want to get in touch head over to belindahumphrey.com or you can find me on Instagram @belindahumphrey_

Disclaimer: Whilst every effort is made to ensure that information is accurate at the time of recording, much like the fashion industry itself, this information may change. 




More Posts