A new study suggests that bio-based materials, often promoted as eco-friendly alternatives to plastics, could pose greater health risks to key species than conventional plastics.
These materials, used in clothing and wet wipes, release microfibers into the environment through laundry, sewage sludge application, and wear and tear, potentially harming ecosystems.
Despite the growing use of bio-based products worldwide, there has been limited research on their impact on ecosystems. A recent study in *Environmental Science and Technology* examined the effects of conventional polyester and two bio-based fibers, viscose and lyocell, on earthworms, which play a vital role in soil health.
The results showed that in high concentrations, 30% of earthworms died after 72 hours of exposure to polyester, while bio-based fibers caused significantly higher mortality rates—up to 60% for lyocell and 80% for viscose.
A follow-up experiment using environmentally relevant concentrations of fibers revealed additional impacts on earthworms. Earthworms exposed to viscose fibers showed reduced reproduction, while those exposed to lyocell fibers exhibited slower growth and increased burrowing activity compared to polyester.
The researchers emphasize that these findings highlight the complexity of addressing microplastic pollution and stress the need to thoroughly test bio-based materials before entering the market.
The study, part of the BIO-PLASTIC-RISK project, was conducted by the University of Plymouth and the University of Bath, with £2.6 million in funding from the Natural Environment Research Council.
Dr. Winnie Courtene-Jones, the lead author on the new study and now a Lecturer in Marine Pollution at Bangor University, said: “Over 320,000 tonnes of bio-based and biodegradable fibers were produced globally in 2022, and research shows that substantial quantities of that will end up in the environment. However, evidence of their ecological impacts has been lacking.”
“Our study has shown that bio-based fibers have a range of adverse effects on earthworms – animals that are critical to the functioning of the environment. It highlights the importance of gathering further evidence before alternatives to conventional plastics are widely available.”
The new study builds on earlier research from 2024, which found that exposure to materials used in biodegradable teabags can lead to up to 15% higher mortality in earthworm populations and negatively affect their reproduction. This latest research comes just weeks before the United Nations convenes in Busan, South Korea, for crucial negotiations on a potential Global Plastics Treaty.
Professor Richard Thompson OBE FRS, senior author of the study and Head of the University of Plymouth’s International Marine Litter Research Unit, will be attending the discussions alongside policymakers, scientists, and delegates worldwide.
He added: “It is clear that along with recycling and re-use, tackling plastic pollution will require reducing the quantities of plastics used and produced. There is increasing interest in alternative materials that could be used as substitutes for plastic. Still, this publication further emphasizes the importance of testing new innovations in relevant environmental settings before widescale adoption.”
“I firmly believe it is possible to tackle the plastic pollution crisis, but independent scientific evidence will be critical in helping us avoid unintended consequences as we look for solutions.”
Journal Reference:
- W. Courtene-Jones, F. De Falco, F. Burgevin, R. D. Handy an R. C. Thompson. Are Biobased Microfibers Less Harmful than Conventional Plastic Microfibers: Evidence from Earthworms. Environmental Science & Technology. DOI: 10.1021/acs.est.4c05856
