Bio-based materials may pose greater threat to earthworms than conventional plastics: Study

A groundbreaking study published in the journal “Environmental Science and Technology” has revealed a concerning truth about bio-based fibers: they may pose a greater threat to the environment than traditional plastics. This challenges the prevailing assumption that bio-based materials are inherently eco-friendly and raises serious questions about their widespread use in consumer products.

The research, conducted by scientists at the University of Plymouth and the University of Bath, focused on the impact of different fibers on earthworms, crucial organisms for soil health and ecosystem function. The team compared the effects of conventional polyester with two popular bio-based fibers, viscose and lyocell, commonly found in clothing, wet wipes, and other everyday items.

Shocking mortality rates

Lab experiments by researches have shown, earthworms were exposed to varying concentrations of the different fibers. The results were alarming.

Table: Earthworm mortality rate

"We were surprised by the significantly higher mortality rates observed in earthworms exposed to the bio-based fibers," said Winnie Courtene-Jones, lead author of the study and Lecturer in Marine Pollution at Bangor University. "These findings highlight the urgent need for more thorough testing of these materials before they are widely adopted as sustainable alternatives." The study also revealed that even at lower, environmentally relevant concentrations, bio-based fibers had significant negative impacts on earthworm health. Viscose, reduced earthworm reproduction rates and Lyocell led to slower growth and increased burrowing activity, potentially disrupting soil structure and nutrient cycling.

The biodegradable wet wipe problem

This research has direct implications for products marketed as ‘biodegradable’ or ‘compostable’ such as wet wipes. Many of these wipes contain viscose or lyocell fibers. While these materials may break down faster than traditional plastics, this study suggests they could be releasing harmful substances into the environment during the degradation process, with potentially serious consequences for soil ecosystems.

"Consumers are often led to believe that products labeled 'bio-based' are automatically better for the environment," commented Professor Richard Thompson OBE, Head of the International Marine Litter Research Unit at the University of Plymouth. "This study serves as a stark reminder that we need a more nuanced understanding of the full life cycle impacts of these materials."

More research is needed to fully understand the long-term ecological consequences of bio-based fibers. The researchers have urged manufacturers and policymakers to adopt a precautionary approach, ensuring that these materials are thoroughly assessed for their environmental impacts before they are used extensively in consumer products.

"Over 320,000 tonnes of bio-based and biodegradable fibers were produced globally in 2022," Courtene-Jones opines. "A substantial portion of this will inevitably end up in the environment. We need to ensure we're not replacing one environmental problem with another." Indeed, this study marks a crucial step in understanding the complex environmental impacts of bio-based materials and underscores the need for a more holistic approach to developing truly sustainable alternatives to conventional plastics.