New studies have revealed that bio-based fibers lead to higher mortality rates and decreased growth and reproduction in earthworms—vital organisms for healthy soils worldwide—compared to traditional plastics. This has prompted scientists to recommend that materials being promoted as plastic alternatives undergo thorough testing before widespread application in various products.
Recent research indicates that bio-based materials may present a more significant health threat to crucial species than the conventional plastics they aim to replace.
These materials are often touted as eco-friendly substitutes for plastics and are found in textiles and items such as clothing, wet wipes, and menstrual products.
However, microfibers from these materials can enter the ecosystem through laundry, sewage sludge application as fertilizer, and general wear and tear of textile products.
Even as production and sales of bio-based products rise globally, there has been limited research investigating their potential effects on species and ecosystems.
A recent study published in the journal Environmental Science and Technology examined the impact of traditional polyester fibers alongside two bio-based fibers—viscose and lyocell—on earthworms, which play a crucial role in soil health worldwide.
The study revealed that at high fiber concentrations, 30% of earthworms exposed to polyester died within 72 hours, while exposure to bio-based fibers resulted in significantly higher mortality rates, with lyocell at 60% and viscose at 80%.
In a separate experiment using environmentally realistic fiber concentrations, earthworms living in soils with viscose fibers showed reduced reproduction compared to those in polyester-containing soils. Meanwhile, earthworms in lyocell-containing soils experienced stunted growth and increased burrowing behavior when compared to those exposed to other fiber types.
Researchers emphasize that this study sheds light on the intricate challenges in global efforts to mitigate microplastic pollution. It underscores the necessity of testing new materials proposed as substitutes for plastics before they are broadly introduced to the market.
This research was part of the BIO-PLASTIC-RISK project, led by scientists from the University of Plymouth and the University of Bath, and was supported by a £2.6 million grant from the Natural Environment Research Council.
Dr. Winnie Courtene-Jones, the primary author of the study and now a Lecturer in Marine Pollution at Bangor University, stated: “In 2022, over 320,000 tonnes of bio-based and biodegradable fibers were produced globally, with significant amounts expected to enter the environment. However, there has been a lack of evidence regarding their ecological effects. Our study demonstrates that bio-based fibers adversely impact earthworms—species essential for environmental functioning. It emphasizes the need for more research before these alternatives to conventional plastics are extensively implemented.”
This new research follows findings released earlier in 2024, which revealed that earthworms exposed to materials from biodegradable teabags could suffer up to a 15% increase in mortality and negative effects on their reproduction.
The study comes just weeks before the United Nations convenes world leaders in Busan, South Korea, for crucial negotiations regarding a potential Global Plastics Treaty.
Professor Richard Thompson OBE FRS, a leading author of the study and Head of the University of Plymouth’s International Marine Litter Research Unit, will participate in those discussions with policymakers, scientists, and delegates worldwide.
He remarked: “It is evident that addressing plastic pollution will necessitate reducing the overall use and production of plastics, alongside recycling and reuse efforts. There is a growing interest in alternative materials to substitute plastics, but this research underscores the critical importance of testing new innovations in relevant environmental contexts prior to large-scale adoption. I firmly believe we can address the plastic pollution crisis, but independent scientific proof will be vital in avoiding unplanned consequences as we explore solutions.”
