Microfibre pollution in fashion: are synthetics all to blame?

It’s common for conscious consumers to be concerned about plastic pollution, and to seek to reduce their consumption of it. Given the all round rise of plastic, it’s perhaps not surprising that plastic also exists in the materials making up the garments we wear.

Microfibres, which are considered a type of microplastic, are tiny fibre fragments from garments that enter the environment through wastewater, when we wash our clothes. It is anticipated that, to date, 1.5 million trillion microfibres are present in the ocean, impacting the entire marine ecosystem.

Not all microfibres are microplastics. There are a few different classifications for microfibres:

Synthetic: polyester, acrylic, polyamides, aramids, and polypropylene

Animal: wool and silk

Plant: cotton, linen, jute, kenaf, hemp, flax, and sisal

Man made cellulosic: rayon, viscose, modal, acetate, and lyocell.

Most discussion and literature on microfibre pollution assumes that the problem is largely due to synthetic fabrics.

This makes sense, given that synthetic fibres account for nearly two thirds of global fibre production, and for 14.5% of plastic production by mass. In descending order, cotton, man-made cellulosic fibres, and other plant-based fibres make up the bulk of the other third, while just 1% of annual fibre production today is animal-derived (from wool and silk).

Yet, a 2020 study found that despite the domination of synthetic fibres in current global production, they accounted for only 8% of microfibre pollution compared to 12% from animal fibres and 80% from cellulosic and plant-based fibres.

This conclusion is troublesome for conscious consumers who rightly want to avoid the use of synthetic fibres in their clothing. What this conclusion should tell us however is that it is not just synthetic fabrics that produce microfibre pollution, but animal, plant and cellulosic fabrics too.

“By compiling a global dataset from 916 seawater samples collected in six ocean basins, we show that… oceanic fibres are mainly composed of natural polymers. µFT-IR characterization of ~2000 fibres revealed that only 8.2% of oceanic fibres are synthetic, with most being cellulosic (79.5%) or of animal origin (12.3%). The widespread occurrence of natural fibres throughout marine environments emphasises the necessity of chemically identifying microfibers before classifying them as microplastics. Our results highlight a considerable mismatch between the global production of synthetic fibers and the current composition of marine fibers, a finding that clearly deserves further attention.”

How can animal, plant and cellulosic fibres become polluting microfibres? Don’t they just biodegrade?

The fabrics we wear aren’t as pure as we like to think they are. These non-synthetic fibres are altered due to chemicals used to colour and prolong fabrics during textile production. This processing can impact the biodegradability of fabrics. Basically, a biodegradable material can become non-biodegradable, if it is dyed, coated or processed in a certain way.

Whilst considered biodegradable on land, little is known about the degradation of wool and cellulosic fibres in marine environments. This does not mean that synthetic fabrics are off the hook, but rather, that fashion’s microfibre problem is more complicated than it may first appear, with the assumption that all animal and natural fabrics are better for environments and ecosystems than synthetic being sometimes unclear and inaccurate.

What’s next?

More research needs to be done to understand the ecological impacts and biodegradation rates of natural and synthetic fibres in a range of environmental conditions to assess their potential impacts on environments and ecosystems worldwide.

The use of non-biodegradable dyes and other substances on biodegradable materials must gain further industry attention, should we hope to see a more genuinely biodegradable and less environmentally impactful fashion future. Legislation around the use of these substances could be one path forward.

As citizen consumers, it is important we ask brands questions about the fibres they use, how they are processed, and how this impacts biodegradation. It is important too, that we turn our attention to other material impacts. For example, some cotton is heavily irrigated, while other cotton is rain-fed. When considering greenhouse gas emissions, in comparison to a cotton knit garment, producing a wool knit garment emits 27 times more greenhouse gas-equivalent emissions. There are also ethical implications of materials to consider, from both a human and non-human perspective.

Microfibre pollution is an important aspect of sustainable fashion, but only an aspect. In order to create a total ethics fashion system, we must not only address their impact, but the sustainability and ethical implications of materials far more broadly.