‘Biodegradable’ clothing scam: not falling apart as promised

The study was conducted at the Ellen Browning Scripps Memorial Pier in San Diego, where the ability of natural, synthetic and blended fabrics to “biodegrade” in the ocean was observed for the first time.

for him, ten different types of fabric usedincluding wood-based cellulose (commercially known as Lyocell, Modal and Viscose); natural cellulose (organic virgin cotton and non-organic virgin cotton); bio-based plastic (PLA) labeled as biodegradable and compostable; petroleum-based plastics (polyethylene and polypropylene terephthalate) and Lyocell fabric blends blended with polyester and polypropylene.

Note that clothing made from polyethylene terephthalate is often sold as recycled textiles, and polypropylene is used in disposable medical textiles such as textiles, carpets, geotextiles, packaging materials, and face masks.

How was it done?

Researchers placed Textile samples in containers exposed to continuous flow, both on the sea surface and on the seabed, at a depth of about 10 meters. After the samples were placed, they went to check their condition every seven days, also took photographs and removed small fragments of the duplicate samples so they could examine the fibers in high resolution. The process took 231 days on the surface and 196 days underwater.

Specimens that terminated this phase of the study were transferred to the Experimental Aquarium at Scripps Oceanography, where they were again exposed to controlled sea flow conditions. The results showed that cellulose-based textiles degraded within 30 to 35 days, while petroleum-based and bio-based materials such as polypropylene or PLA “showed no signs of disintegration” after 428 days.

“Natural cellulose-based materials broke down in about a month, so we switched to a new sample after the old one was broken down,” said Sarah-Jeanne Royer, lead author of the study. “While natural samples are changed five times, plastic samples remained the same for over a year”.

In a more detailed analysis of the behavior of the fibers of these textiles, Dimitri Deheyn, who is also principal investigator, confirmed that while natural fibers gradually thin out, plastic fibers retain their diameter without showing signs of biodegradation.

Similarly, study co-author Francesco Greco at the Northwest China University Department of Geology performed Raman spectroscopy analysis by observing the structural chemical degradation of the fibers. Greco found While there have been “significant changes” in the chemical footprint of cellulose-based materials, “bio” and petroleum-based plastics have not.

For textiles combined with natural fiber and plastic yarns, The study shows that the plastic part remains intact, only the natural part deteriorates. And this is despite the fact that they are materials promoted as the most sustainable alternative.

In the third step, the researchers transferred the samples to an independent company to send them to a closed system inside a bioreactor where the marine environment was regenerated. It is a piece of equipment that can measure the percentage of carbon dioxide produced by microbial activity that uses fabrics as nutrients, thereby measuring the biodegradability of materials. The results were the same: Cellulose-based materials showed complete biodegradation in 28 days, while petroleum-based or bio-based textiles showed no signs of biodegradation.

“Important source of pollution”

With these results, the researchers note that: Marketed as “ecologically promising” materials, plastics are eventually becoming “significant sources of pollution” originates from humans”, so they stress the need to continue researching its impact on the environment to raise awareness.

“Consumers concerned about contamination of microfiber plastic should be cautious about the materials they purchase,” said Royer. “All we should tend to buy less clothesOpt for high-quality cellulose-based materials like cotton, merino or wool that will last longer, or look for more circular and sustainable options that reuse items like clothes swapping.”

They also underline The need to establish standardized tests to check whether materials decompose as promised on their labels and promotional messages where it is described as “biodegradable” or “compostable” in a new instance of “greenwashing” or “ecostate”.

“This comparative study highlights how important our language is when it comes to plastics,” Deheyn said. “Actually, A bioplastic like PLA is often assumed to be biodegradable in the environment because it contains the prefix ‘bio’, in fact it is nothing like that.”.

Reference work: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0284681

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Contact details of the environment department: crisisclimatica@prensaiberica.es