Often seen as eco-friendly alternatives to conventional plastics, bio-based materials may actually pose a greater risk to some key species than the plastics they are designed to replace, says a new study published in Environmental Science and Technology. Commonly found in textiles, clothing, wet wipes, and period products, these materials shed microfibers into the environment during laundering, the application of sewage sludge as fertilisers, and general wear and tea.
According to this study, in high concentrations, polyester fibers caused a 30 per cent mortality rate among earthworms after 72 hours, whereas bio-based fibers led to even higher death rates, with lyocell killing up to 60 per cent and viscose up to 80 per cent of earthworms. In another experiment simulating real-world fiber concentrations, soils containing viscose fibers hindered earthworm reproduction, while lyocell fibers led to reduced growth and greater burrowing activity.
Led by researchers from the University of Plymouth and the University of Bath as part of the Bio-Plastic-Risk project, this study emphasises the importance of extensive testing before the wide adoption of alternatives to plastics. Dr Winnie Courtene-Jones, Lead Author and Lecturer- Marine Pollution, Bangor University, emphasises, the study highlights the adverse effects of bio-based fibers on earthworms, which are critical to the environment’s functioning. It also emphasises on the importance of gathering further evidence before the adoption of various new alternatives to conventional plastics.
This research follows earlier findings published in 2024, which revealed that earthworms exposed to materials in biodegradable teabags experienced higher mortality rates and reproductive challenges.
Professor Richard Thompson, Head, International Marine Litter Research Unit, University of Plymouth notes, reducing plastic pollution requires not only recycling and re-use but also careful consideration of alternative materials. While addressing the plastic crisis, it is important to gather independent scientific evidence, he adds.
