In this day and age, who isn’t familiar with microplastics? The nearly indestructible bits of plastic that break off from common plastic items?
As we study them more, we’ve found out that they’ve lodged themselves in unexpected places like our arteries, lungs, even placentas; as well as oceans and soil.
And why is that? Because we all know by now that it takes 100 to 1000 years for plastics and microplastics to break down.
Since there will be a significant reduction of plastic use any time soon, it’s safe to assume that the plastics are going to pollute us more and more each day.
Isn’t that nice?
Well, that’s why scientists have been trying to find alternatives to regular plastics and microplastics.
The good news is, some have done that. For instance, there’s new research by scientists at the University of California San Diego and Algenesis–a materials science company.
It reveals that their plant-based polymers break down, even at the microplastic level, in less than seven months. The research is published in Scientific Reports.
Co-author Professor Michael Burkart stated that we, humanity, were only beginning to comprehend the impact of microplastics on the environment and health.
“We’re trying to find replacements for materials that already exist, and make sure these replacements will biodegrade at the end of their useful life instead of collecting in the environment. That’s not easy,” said Burkart, who is also the co-founder of Algenesis.
“When we first created these algae-based polymers about six years ago, our intention was always that it be completely biodegradable,” added co-author and Algenesis co-founder Robert Pomeroy.
“We had plenty of data to suggest that our material was disappearing in the compost, but this is the first time we’ve measured it at the microparticle level,” Pomeroy went on.
Biodegradability testing
To check its biodegradability, the team ground their product into fine microparticles. They also used three different methods to confirm that when placed in compost, microbes were breaking it down.
First, they used a respirometer. Microbes release carbon dioxide (CO2) when breaking down compost material, which the respirometer measures. Results were then compared to cellulose breakdown, considered the gold standard of biodegradability.
The plant-based polymer matched cellulose at almost 100%.
Next, they employed water flotation. Since plastics don’t dissolve in water and float, one can easily scoop them off.
At 90 and 200-day intervals, almost 100% of petroleum-based microplastics were recovered, indicating no biodegradation.
But after 90 days, only 32% of algae-based microplastics were recovered, showing over two thirds had biodegraded. After 200 days, only 3% was recovered, indicating 97% had vanished.
The final measurement involved chemical analysis using gas chromatography/mass spectrometry (GCMS). It detected the original plant materials, indicating the polymer was breaking down.
Scanning-electron microscopy showed how microorganisms colonize the biodegradable microplastics during composting.
Another co-author Stephen Mayfield said, “This material is the first plastic demonstrated to ‘not’ create microplastics as we use it.
“This is more than just a sustainable solution for the end-of-product life cycle and our crowded landfills. This is actually plastic that is ‘not’ going to make us sick.”
No mass production yet
There’s no denying that this is all good news. But for now, biodegradable microplastics are just a part of the long road to viability.
The real challenge is adapting the new material to existing manufacturing equipment designed for traditional plastic. And as we all know, it’s not easy to overcome that challenge.
So far, Algenesis has partnered with some companies like RhinoShield for cell phone cases using UC San Diego’s plant-based polymers.
“When we started this work, we were told it was impossible. Now we see a different reality. There’s a lot of work to be done, but we want to give people hope. It is possible,” Burkart said.
Previous similar finding
Before the authors at Algenesis presented their findings, there was a similar study that showed a similar biodegradable solution.
Back in 2022, marine biologist Samantha Clements worked together with UC San Diego researchers. They conducted tests on biodegradable polyurethane materials.
These materials are used in foams for the first commercially available biodegradable shoes sold by a company called Blueview.
The tests were carried out at Scripps’ Ellen Browning Scripps Memorial Pier and Experimental Aquarium.
This location was chosen because it offered scientists access to the natural nearshore ecosystem, where rogue plastics often end up.
The team observed that various marine organisms colonized the polyurethane foam. The organisms also broke down the material into its starting chemicals in the ocean environment.
These chemicals served as nutrients for microorganisms–a mix of bacteria and fungi, which are prevalent in the marine environment.
Biologist at the UC San Diego Stephen Mayfield said, “We’ve shown that it’s absolutely possible to make high performance plastic products that also can degrade in the ocean.
“Plastics should not be going into the ocean in the first place, but if they do, this material becomes food for microorganisms and not plastic trash and microplastics that harm aquatic life”
The researchers exposed the samples to tidal and wave dynamics and examined their molecular and physical changes. They used Fourier-transform infrared spectroscopy and scanning electron microscopy.
Results indicated that the material began to degrade in as little as four weeks.
The researchers also identified microorganisms from six marine sites around San Diego capable of breaking down and consuming the material.
Mayfield said, “I was surprised to see the multitude of organisms colonizing these foams in the ocean. It becomes something akin to a microbial reef.”
Will the fish be okay, though?
The two studies by UC San Diego might address concerns from those who worry that biodegradable plastics still harm fish.
In 2023, the University of Otago showed that biodegradable plastics, thought to be better, can still have a negative impact.
We already know how oil-based microplastics are bad for marine life. And so far, we still don’t fully understand the impact of biodegradable alternatives.
Published in the Science of the Total Environment, this study was the first to examine how petroleum-based and biodegradable plastics affect wild fish.
Lead author Ashleigh Hawke found that exposure to petroleum-based plastics negatively affected fish in terms of escape performance, routine swimming, and aerobic metabolism.
On the other hand, fish exposed to biodegradable plastics only saw their maximum escape speed reduced.
Hawke stated that this research highlighted how both types of plastics can have a negative effect on marine fish. That is, when they come into contact with them.
“Biodegradable plastics may not be the silver bullet to plastic pollution as we believe them to be. 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,” Hawke said.
In addition, co-author Dr Birdie Allan underscored the need for more policy action on both types of plastics to conserve 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,” Dr Allan said.
However, it should be noted that this research used biodegradable plastic from the University of Otago. It’s unknown if the results would be different or the same had they used that of UC San Diego.
This goes to show that there’s variability in biodegradable plastics, as they’re relatively new.
All of the studies here also show that extensive use of plastics is unwise, despite the new, more eco-friendly alternatives.
Sources:
https://phys.org/news/2024-03-biodegradable-microplastics-based-polymers-months.html
https://www.sciencedaily.com/releases/2023/10/231018194548.htm
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