A recent study has suggested that bio-based fibres, often marketed as environmentally friendly replacements for plastics, may pose greater ecological threats than previously assumed. Conducted by the University of Plymouth and the University of Bath as part of the £2.6 million BIO-PLASTIC-RISK project, the research reveals that these fibres, used in everyday items like clothing and wet wipes, can release microfibres that harm ecosystems, particularly through laundry wastewater, sewage sludge, and wear-induced fibre shedding.

Comparing Bio-Based Fibres with Conventional Plastics

In a detailed analysis, scientists compared the impact of conventional polyester with two common bio-based fibres, viscose and lyocell, on earthworms—species vital to soil health. The findings showed that bio-based materials might be significantly more hazardous. In lab tests, up to 80% of earthworms exposed to viscose fibres died, compared to 30 percent mortality among those exposed to polyester. When exposed to lyocell, 60 percent of earthworms did not survive. At lower, environmentally relevant exposure levels, viscose was linked to lower reproduction rates, while lyocell led to reduced growth and altered burrowing behaviours.

Importance of Rigorous Testing for New Materials

Dr. Winnie Courtene-Jones, a Lecturer in Marine Pollution at Bangor University and lead author of the study, pointed out the critical need for more comprehensive testing. She noted that while bio-based and biodegradable fibres are produced in large volumes—over 320,000 tonnes in 2022—insufficient data exists on their environmental impacts. “Our study underscores the importance of evidence-based approaches before rolling out new materials that aim to replace conventional plastics,” Dr. Courtene-Jones stated, highlighting that ecological impacts, especially on soil health, must be factored into evaluations of bio-based products.

Implications for the Future of Plastic Alternatives

This study, which builds on prior research linking biodegradable tea bags to increased earthworm mortality, arrives ahead of key discussions on plastic pollution at the upcoming United Nations conference in Busan, South Korea. Professor Richard Thompson, Head of the University of Plymouth’s International Marine Litter Research Unit, emphasised the need for an evidence-based strategy. He remarked, “Reducing plastic pollution is essential, but this research shows that substitute materials must undergo rigorous environmental testing to avoid unintended consequences.”