‘Biodegradable plastics may not be the silver bullet to plastic pollution as we believe them to be.’
DUNEDIN, New Zealand — Biodegradable plastics are often hailed as a helpful step in the right direction toward fighting plastic pollution, but noteworthy research is throwing cold water on that idea. Scientists at the University of Otago report that biodegradable plastics are still harmful to fish.
Previous studies have established that petroleum-derived microplastics have a negative impact on marine life, but far less is known about the influence of biodegradable plastic alternatives under the sea. Most plastics are petroleum-based and can take hundreds or even thousands of years to break down. Biodegradable plastics, on the other hand, decompose in response to biological conditions (bacteria, water, etc).
This latest project, funded by a University of Otago Research Grant, is the first ever to analyze the impact of both petroleum-derived plastic and biodegradable plastic on wild fish.
Lead study author Ashleigh Hawke, who completed a Master of Science in Otago’s Department of Marine Science, explains that petroleum-derived plastic exposure usually negatively affects fishes’ escape performance, routine swimming, and aerobic metabolism.
On the other hand, fish exposed to bioplastics saw their maximum escape speed slow considerably. So, while petroleum-derived plastics are worse for fish, biodegradable products still aren’t doing aquatic life any favors.
Researchers believe their research is significant because it showcases how both petroleum-derived plastics and biodegradable plastics can be damaging to marine fish upon exposure.
“Biodegradable plastics may not be the silver bullet to plastic pollution as we believe them to be,” says Hawke in a media release. “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.”
“The development of traditional plastics has been well established for decades and so there is little variation in the production of them. However, because biodegradable plastics are a relatively new area, there is variation in the way they are manufactured and the materials that are being used,” concludes study co-author Dr. Bridie Allan, also of the Department of Marine Science, who adds more must be done at a policy level to protect marine environments.
“This research shows that the raw materials used in these products matters and that the use of them should be more regulated and controlled.”
The study is published in the journal Science of The Total Environment.
