No “silver bullet”: Research finds biopolymers can cause negative health effects among fish

23 Oct 2023 --- Research from the University of Otago, New Zealand, has shown that biodegradable plastics harm fish when tossed in the ocean. Petroleum-derived microplastics impact marine life, but little is known about the impact of biodegradable alternatives, leading scientists to conduct research in the field.

The study, published in Science of the Total Environment and funded by a University of Otago Research Grant, is “the first” to assess the impact of petroleum-derived plastic and biodegradable plastic on wild fish.

Lead author Ashleigh Hawke, who completed a Master of Science in Otago’s Department of Marine Science, says petroleum-derived plastic exposure negatively affected the fish’s escape performance, routine swimming and aerobic metabolism.

Meanwhile, bioplastic exposure caused fish to have their maximum escape speed negatively affected. Hawke asserts that the research is significant as it demonstrates that petroleum-derived and biodegradable plastics can damage marine fish when in contact.

“Biodegradable plastics may not be the silver bullet to plastic pollution as we believe them to be,” says Hawke.

“Although they are not as bad, they can still cause negative effects to those animals that may be exposed to them — in the case of this study, populations would decline as their escape behaviors are impaired.”

Bioplastic exposure can cause fish to have their maximum escape speed negatively affected.Relatedly, Swedish researchers found that single-use paper cups could be as toxic to environmental and human health as plastic.

Dr. Bethanie Carney Almroth, professor of ecotoxicology and environmental science at the Department of Biological and Environmental Sciences, University of Gothenburg, Sweden, told Packaging Insights that the findings show labels like “biodegradability” are often misleading.

Policies for marine protection
Co-author Dr. Bridie Allan, also of the Department of Marine Science, says more needs to be done at a policy level to protect marine environments.

“The development of traditional plastics has been well established for decades and so there is little variation in their production. However, because biodegradable plastics are a relatively new area, there is variation in how they are manufactured and the materials used,” says Allan.

“This research shows that the raw materials used in these products matters and that their use should be more regulated and controlled.”

In other bioplastics news, researchers from the University of Washington, US, developed new bioplastics made from spirulina that they claim degrades in three to four weeks — the same rate as a banana peel in a backyard compost bin.

Meanwhile, the University of California in San Diego, US, released a book on algae-based biodegradable plastics and their potential to change consumerism globally.

Edited by Natalie Schwertheim