Fast fashion bioplastic study raises greenwashing fears but leaves industry irritated

06 Jun 2023 --- A “first-of-its-kind” study has found that synthetic textiles, including “compostable” plastics like polylactic acid (PLA), do not degrade after more than a year in the ocean. But the bioplastics industry has dismissed the findings as irrelevant, pointing out that the fashion industry does not use PLA because it is “compostable” but because it is bio-based and avoids fossil-based resources.

The new study from UC San Diego’s Scripps Institution of Oceanography in the US – published in PLOS One – found that while the cellulose-based textiles repeatedly disintegrated in 30-35 days, the oil-based (PE and PP) and bio-based (PLA) materials showed no sign of disintegration after 428 days.

Lead author Sarah-Jeanne Royer – who tells us she was “very surprised” that PLA showed no sign of degradation – has called for clearer marketing regulations around “compostable” plastics and consumers to make more responsible choices, stressing that “what might biodegrade in an industrial setting does not necessarily biodegrade in the natural environment.”

While the European Bioplastics (EUBP) association has consistently argued for brands to specify the environment in which bioplastics degrade and offer proof according to related standards, it sees “no real value” in the study.Sarah-Jeanne Royer: Consumers should buy fewer garments and choose high-quality, cellulose-based materials.

“Everybody knows that if you wash your clothes, you have a certain abrasion of particles that end up in the environment, which is for sure an issue,” Constance Ißbrücker, deputy managing director and head of environmental affairs at EUBP, tells PackagingInsights.

“No one would ever claim that PLA is ‘marine-biodegradable’ – this is basic scientific knowledge for polymer experts. PLA is only used and certified for industrially compostable packaging and applications, and it degrades effectively in such facilities.”

The language of plastics
Fiber blends, which interweave natural fiber strands with bio- or oil-based plastic strands, are often promoted as a more environmentally sustainable alternative to textiles made entirely from synthetic plastics, according to the study authors. The study showed that only the natural part of the fiber degraded, with the plastic portion remaining intact.

“This comparative study highlights how crucial our language is around plastics,” says Scripps marine biologist Dimitri Deheyn, senior author of the study. “A bioplastic like PLA, commonly assumed to be biodegradable in the environment because it contains the prefix ‘bio,’ is actually nothing like that.”EUBP points out that experts would never claim PLA is “marine-biodegradable,” but it can support circularity.

The study authors note that PLA and oil-based plastics represent a significant source of human-caused pollution. How these materials behave in a natural environment must be further explored, they stress.

Like EUBP, the study authors are urging regulators to establish standardized testing methods and specifications, like those employed in their study, and clearer rules around definitions and claims, to ensure materials are appropriately marketed.

“Testing degradability only in natural seawater is not sufficient, and hence we complemented the study with some closed-system experiments. We also looked at the chemical signature to investigate degradation at the level of individual fibers and used scanning electron microscopy to visually look at the fibers and measure their diameters over time,” Royer tells PackagingInsights.

But EUBP argues that even within the study, it is not clear if the materials tested are certified. “The PLA in the study was not from one of our member companies, and it is unclear if it was certified and tested, even for industrial compostability,” says Ißbrücker.

“The authors should make clear if there was a certification because certification is not only related to biodegradation behavior but also ensures that the material has no ecotoxic effects and does not contain hazardous substances.”

Problems or distractions?
The study authors imply that the study could have major implications for packaging since the industry has a large carbon footprint. Packaging also typically comprises single-use items made from low-quality grade materials.

“Hence, using PLA for packaging won’t be a solution given that a high amount would end up in the environment and most consumers don’t have access to composting facilities to properly discard the material,” says Royer.

The textile samples were placed in flow-through containers and deployed at the sea surface and seafloor.In light of the study, the researchers hope consumers will become more aware of the power of their own choices: “Consumers who are concerned about microfiber plastic pollution should be mindful of the materials they are buying,” adds Royer.

“We should all aim to buy fewer garments, opt for high-quality, cellulose-based materials like cotton, merino or wool that will last longer, or look to more circular options that repurpose items like clothing swaps and Buy Nothing groups.”

However, EUBP maintains that such studies create nothing more than an increasingly frequent distraction for bioindustry innovators. 

“You see these kinds of studies more and more, where someone makes a big thing out of a scientific fact that is known to everybody. This is annoying for our industry because we are always put on the defensive,” says Ißbrücker.

“It’s doing harm to the industry because some of the articles related to the study suggest that the industry was marketing its materials as a solution to the plastic pollution problem, but this is simply not true. Bioplastics have a clear role in a circular economy.”

Innova Market Insights recently identified “Green but clean” and “Renewable rebellion” as top packaging trends for 2023, noting that consumers increasingly want more environmentally sustainable options, but without being misled.

By Joshua Poole