A pair of jeans can release 56,000 microfibers per wash

Originally published at: https://boingboing.net/2020/09/09/a-pair-of-jeans-can-release-56.html

Who is washing their jeans that often tho?


I was kind of surprised that a cotton garment would be considered problematic, considering the cotton fibers should degrade over time, and as plant material would (presumably) be not that different from natural plant material entering water bodies.

So I thought, maybe they are referring to jeggings or stretch jeans or something else with synthetic materials… but according to the abstract the material they are looking at is “anthropogenically modified cellulose”.

OK, what is that? A quick search reveals… articles about this study.

Have they invented some new term to make cotton fiber sound scary? Or do small fibers, regardless of their material, cause environmental problems – and it turns out that even presumably degradable materials do persist long enough to cause trouble? In the abstract, at least, I don’t see any specific references to harms caused by this material, whatever it is.

Scientists who know more, please enlighten me!


ETA: or…


Patagonia leads the way, as usual.


I admit I am wearing a pair of Levi’s right now, and it says on the inside I should wash them less.

Which I alway did. But never is not working for this particular motorically challenged mutant…


I was wondering the same thing. I get how microplastics are a problem, but cotton fibres? The biodegradability of cotton is one of the reasons I like it (its issues with pesticide and desertification notwithstanding).


Levi’s has recently started selling a line of jeans and garments made out of it with specially processed hemp. From memory they said hemp hasn’t typically been used for jeans because its a rougher material but they’ve managed to get the right feel. I’m sure they’re not the only ones but would be keen to see more hemp based clothing if it is grown more sustainably than cotton.


That would be chemically-treated plant fiber and anything else anthropogenically-created derived from the environment of said fiber.

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Maybe it’s more about the chemicals leaching out of the treated cotton microfibres? Also, as long as they break down into non-harmful components, they should be captured and consumed in the sludge at wastewater treatment plants. So don’t old-timey wash them on a washboard in the local river.

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Most jeans these days contain at least some synthetic material, and women’s jeans a lot more than men’s.

You can find 100% cotton jeans but I’ve found they’re becoming rarer and rarer…

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Are they? Pretty sure every single jeans i have are 100% cotton, even the one i bought last month. I would expect the “flex” variants of jeans would not be 100% though but that seems pretty obvious.


I can’t imagine that cotton is the problem either no hope someone chokes in because otherwise this study sounds “trumped up”. That said allot of cheap denim manufacturers (these days that’s jeans under $50) do add allot of poly to their blends. Cotton has gotten very expensive. I worked in fashion for a while and back around 2012 even the denim’s manufacturers were freaking out about the availability, demand and surge pricing of cotton.

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Ok, I was also very curious, so I read the article. https://doi.org/10.1021/acs.estlett.0c00498
Some relevant quotes:

“Fibers consisting of natural materials can be further categorized as proteinaceous, cellulosic, or mineral (FigureS1). “Natural” fibers used in textiles are modified by the addition of chemical additives and treatments.27,28 We define cellulosic fibers with evidence of anthropogenic modification,such as the presence of chemical additives (including dyes) or manufactured morphology, as anthropogenically modified cellulose (AC). For example, while indigo denim is composed of cotton, a natural cellulosic fiber, it is highly processed and contains synthetic indigo dye as a colorant of the warp thread and other chemical additives that improve textile durability and performance.”

“Denim microfibers are a form of“natural”microfiber;however, they are chemically processed28and are sufficiently persistent to undergo long-range transport and accumulate in environmental compartments, where they could be of concern for biota. 11,16−18 Here we show, for the first time, that blue jeans, the world’s most popular single garment, have a widespread geographic footprint in the form of microfibers in aquatic environments from temperate to Arctic regions. In fact, these “natural” microfibers are often more abundant than synthetic microfibers in environmental samples. Thus, our findings expose a new front in the challenge of microfiber pollution,“natural” fibers. Our results also contribute to the large body of evidence documenting global anthropogenic pollution, of which microplastics and now microfibers have captured public attention as very real manifestations of that pollution.”

The articles they’re citing (I didn’t read these) after saying the persistent “natural” microfibers could be of concern for biota are: https://dx.doi.org/10.1016/j.watres.2020.115623 , https://dx.doi.org/10.1016/j.marpolbul.2017.08.057 , https://dx.doi.org/10.1016/j.scitotenv.2020.136973 , https://dx.doi.org/10.1007/s10933-019-00071-7

I’m still shrugging a big shrug, but I think that’s fine. All they’re trying to show is the extent of the pollution being caused by washing blue jeans. I don’t think it’s so important if the pollution is actually harmless. And they’re only interested in blue jeans because they found it was easy to identify the indigo dyed fibers, so it’s an easy metric to work with.


Lemme tell you about the metric craptons of macrofibers and microfibers released by the cottonwood trees round these parts…


I did a quick search on some other sources, and in fact this paper might be reporting relatively good news. Previous studies had assumed that almost any dyed fiber fell in the category of “microplastics” - and dyed cellulose was presumed to degrade too fast to detect. A quick troll didn’t turn up anything suggesting that cellulose microfibers were harmful, just a bunch of papers saying that they were there in previously unsuspected numbers (and therefore that the polyester, polypropylene, etc. fibers were present in correspondingly reduced numbers).

The idea that cellulose microfiber pollution may be relatively benign to life is supported by the fact that in the paper cited, the researchers also sampled the digestive tracts of rainbow smelt and found only one cellulose fiber in all the fish sampled. (These are bottom feeders - they surely ingest them, but they do biodegrade.)

The methods of the paper would not be able to detect undyed cellulose, which has to be there in great quantities. In certain seasons, the waterways near me are absolutely matted with the cypselae of Asteraceae such as dandelions and thistles, Asclepiaceae such as milkweeds, and Salicaaceae such as cottonwoods, poplars and weeping willows.

There are certainly toxic blue dyes that the microfibers could carry, but virtually all blue jeans are dyed with indigo or woad, not synthetic dyes.

The other articles that I came across were all popular-press articles written by ‘environmentally aware’ people who simply quoted the statistics of number or mass of cellulose fibers released, and obviously making the assumption that all anthropogenic pollution is equal.

Human life cannot exist without releasing some anthropogenic material into the environment, pretty much by definition.


Yeah… like very rarely here…

Also - isn’t denim just cotton? Why isn’t cotton breaking down in the environment?

Microfibers from plastic based clothing I can see as being an issue as they take way longer to break down. I’d be fine with all cotton and wool clothing… or hemp!

My understanding is that blue jeans are dyed with synthetic indigo. I am not sure how similar the synthetic indigo is to plant derived indigo.

Modern blue jeans are often dyed using a process that includes cyanide.

… By 1882, however, indigo was being synthesised, and producing denim blue now involves large quantities of petroleum, as well as toxic substances such as formaldehyde and cyanide.

Meanwhile, because indigo isn’t water soluble, more toxic chemicals - corrosive to workers and deadly to marine life - need to be added to turn it into a liquid dye…

(Commercial denim industry scaled up and cut processing times using doubleplus ungood synthetic indigo chemistry.)

Originally blue jeans were dyed with indigo, from a plant, that oxidizes, turning [natural plant] fiber blue.

These days, other dyeing methods are being studied as an alternative to using toxic dyes:

My guess is that microfibers are, among other things, a vehicle for further transporting toxic substances, in addition to whatever is in solution as the laundry wash-water goes to… to… its next stop in the wastewater system at hand. No idea how persistent these fibers and their unwelcome chemical hitchhikers are in their “final” landing spot. Fate and transport of this stuff could mean groundwater contamination, soil contamination, etc. especially if heavy metals, plastics, and other nonbiodegradables are involved.

I get it that it is the dose that makes the poison… but sometimes, a lot of tiny seemingly harmless things add up to a big problematic thing.

I can certainly imagine scenarios where microfibers, and especially microfibers loaded with toxics, can unbalance a fragile ecosystem [insert “more research is needed” gif here].

Marine life, aquatic life are unfortunate recipients of wastewater outfall pollutants. Ye gods:

Patagonia freaked out when they figured out that their lovely fleece jackets and vests were polluting our planet, and Yves Chouinard runs a damn fine company possessing what is usually a sterling environmental record:

NB: Not all wastewater systems are the same, and not all wastewater systems are superbly implemented to safeguard the environment and all life forms. There is an art and science to the “laundry-to-landscape” greywater system.

Disclosure: I have worked with and for greywater designers, engineers, end users on greywater projects.

ETA: clarification re synthetic indigo v natural indigo


So…wear less pants? Working from home during the pandemic, I don’t think it’s possible for me to wear less pants. :stuck_out_tongue_winking_eye:


Que sabor de Latin in your neck of the woods!

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