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Dear Dot,
I was on a company's website, and it listed a sweater vest made with linen, cotton, and “biodegradable polyester,” described as “an innovative fibre that biodegrades at rates similar to natural fibers such as wool in landfill conditions, all the while reducing synthetic microfibre pollution.” Is that legit?
– Lizanne
The Short Answer: “Biodegradable polyester” requires an industrial facility to break down. If it ends up anywhere else, it impacts the environment the same as regular polyester.
Dear Lizanne,
Kudos to you for reading the fine print on your labels! But your very interesting question is one that Dot has decided to relegate to Dot Junior, who recently graduated from a fashion design program, so her combination of fashion expertise and access to textile experts can better inform an answer. Take it away Dot Junior:
While attending a fashion design program, I learned about designers and manufacturers that are quite literally trying to weave sustainability principles into fashion. But I’m frustrated at the amount of greenwashing in the fashion industry. Clothing brands are trying to keep up with consumer demand for sustainability (which we love), but I’ve noticed a lot of claims that seem too good to be true. Are they? Let’s take a look at what experts are saying and figure this out.
Before we get into biodegradable polyester, let’s get on the same page about what, exactly, regular old polyester is. In simplest terms, polyester is a type of plastic. And what is the main ingredient in plastic? Crude oil — noxious from drilling to disposal. Very importantly, polyester doesn’t break down (biodegrade) the way organic fibers do. Rather, it sticks around forever, in a landfill, or wherever else it ends up. Fun fact: if you try to light polyester on fire, it will melt (I may or may not have tried this, but you definitely should not). Materials like cotton will burn and turn to ash. Unfortunately, since emerging on the fashion scene in the ‘50s, polyester has become ubiquitous in our clothes, often mixed with natural fibers. You and I both probably wear plastic every day. It’s cheap, it’s versatile, and it’s easy to care for.
All of which is to say, the notion of biodegradable polyester is exciting. Affordability with a reduced environmental price tag? Yes, please. But first, let’s see if claims hold up.
We’ll start by acknowledging that the production of any textile requires energy — often derived from fossil fuels — and raw materials. That is simply a fact of consumption.
Regarding biodegradability, let me dust off my chemistry textbook: In (somewhat) scientific terms, biodegradable polyesters are biopolymers (a polymer is a long chain of molecules) designed to biodegrade quickly, and they can replace fossil-fuel/crude-oil based synthetic polymers. The most commonly used biopolymer for textiles is PLA (Polylactic Acid), sourced from fermented natural fibers from corn, potato, and other agricultural products.
So, does that mean it’s biodegradable?
Technically, yes; but, according to Dr. Susanne Brander, an ecotoxicologist from Oregon State University, “biodegradable polyester does break down faster, but [only] under certain conditions.” PLA will only ever so slightly degrade in natural compost conditions (ie. your backyard compost). It only degrades entirely if it’s composted in an industrial facility, which utilizes extreme heat and humidity to break the chemical bonds within the compound. So yeah, it is biodegradable, but only in an industrial compost facility.
What about its contribution to plastic pollution?
A study from UC San Diego tested the biodegradation of a variety of textiles, including PLA, in the ocean. After being submerged for more than a year, PLA had not begun to biodegrade at all. (For context, the natural fibres tested alongside PLA took only a month to biodegrade under the same conditions.)
What’s more, any polyester sheds microfibres throughout its lifespan. “We suspect microfibers are more toxic because they are more difficult to excrete — I’m talking about all living organisms including us; they get caught in tissue, all microfibers,” Dr. Brander says, “and also possibly because of the chemicals they are manufactured with or that they absorb in the field. They also hang out longer in the water column and can be easily inhaled in homes etc. [Microfibers are] what we find the majority of in our marine and aquatic samples.” Textile and plastic waste is notorious for polluting our water and environment, so if PLA ends up anywhere but an industrial composter, it has a similar effect on our environment to that of regular polyester. Dr. Brander’s prescription is simple: Purchase and wear natural fibers.
I conclude that calling certain polyesters “biodegradable” is an overly generous statement. While it is technically true, it doesn’t give consumers the whole picture, as these plant-based polyesters aren’t biodegradable the way that wool and cotton and linen are. We understand that polyester has appealing properties that are hard to find in natural fibers, and consequently, many of us have at least some polyester in our wardrobes. (If you do, there are steps you can take to reduce the shedding of microfibers. Dot has tips.) But while we applaud the industry’s aim to create more sustainable textiles, we can’t get on board with claims that don’t stand up under scrutiny and that add to greenwashing in the fashion industry.
Skeptically,
Dot Junior
