Of the 18 selected fungal strains, four proved to be particularly “hungry”, which means they could efficiently utilise plastics, especially polyurethane which is used to make construction foam…
TreeTake Network
A fungus living in the ocean can break down a major source of marine pollution a new study reports. Scientists have discovered a possible new tool for addressing the growing problem of plastic pollution in the world's oceans. A recently published study by an international consortium of researchers details a marine fungus called Parengyodontium album which lives on plastic litter in the ocean. The fungus is capable of breaking down polyethylene particles — the most prevalent commercial plastic in the ocean — once the plastic has been exposed to ultraviolet light. The team also discovered the amount of time it takes for fungus to do its job. But they warn that their work is likely to be only a small part of solving plastic pollution, and say there is still a need to reduce food packaging and other debris from entering the environment where it can take decades to degrade.
“Marine fungi can break down complex materials made of carbon. There are numerous amounts of marine fungi, so it is likely that in addition to the four species identified so far, other species also contribute to plastic degradation. There are still many questions about the dynamics of how plastic degradation takes place in deeper layers," lead study author Annika Vaksmaa, of the Royal Netherlands Institute for Sea Research, said in a news release. "What makes this research scientifically outstanding, is that we can quantify the (plastic) degradation process."
The discovery was the product of international scientific collaboration between study authors at the Royal Netherlands Institute for Sea Research and researchers from Utrecht University, the Ocean Cleanup Foundation, and research institutes in Paris, Copenhagen, and St Gallen, Switzerland. A large number of bacteria types are known to be able to break down plastic. But Parengyodontium album is the latest of just four known marine fungi species able to degrade plastic.
“The most surprising finding of our work ... is that our fungi could exclusively grow on some of the synthetic polymers and even form biomass,” Hans-Peter Grossart, head of the research group at the Leibniz Institute of Freshwater Ecology and Inland Fisheries, informed. Grossart believes the microbial plastic destroyers could be used in sewage treatment plants or other facilities with controlled conditions. However, the fungi are unlikely to be a solution for stemming the global flood of waste. “We should definitely try to release as little plastic as possible into the environment,” Grossart added. “Plastic is made from fossil carbon and if the mushrooms break it down, it’s no different to us burning oil or gas and releasing CO2 into the atmosphere.”
An analysis at Lake Stechlin in north-eastern Germany into how microfungi thrive on some plastics with no other carbon source to feed on has clearly demonstrated that some of them are capable of degrading synthetic polymers, said the team leader. Of the 18 selected fungal strains, four proved to be particularly “hungry”, which means they could efficiently utilise plastics, especially polyurethane which is used to make construction foam. Polyethylene, used in plastic bags and packaging, was much slower to degrade, and microplastics from tyre abrasion were the most difficult, largely because of additives like heavy metals. Grossart said he believed the fungi’s ability to utilise plastic was an adaptation to the vast amounts of plastic carbon in the environment. However, their enzyme activity is heavily dependent on external conditions, such as temperature or micronutrients.
Some 390 million tonnes of plastic were produced worldwide in 2021, data from the Plastics Europe Plastics Producer Association show, up from 1.7 million tonnes in 1950. Although the recycling rate has increased in the last few years, less than 10% of plastic waste is recycled worldwide. Researchers noted that humans annually produce more than 400 billion kilograms of plastic, an amount that is expected to triple by the year 2060. Plastic pollution, including microplastic debris, has been linked to human infertility as well as reproductive drops in several forms of marine life — and is considered to be a long-standing cause of ecological disruption. The White House recently announced an initiative to address so-called "forever chemicals," a prominent byproduct of plastic pollution and waste.
A new UN report says the plastic pollution crisis, while dire, is solvable
Plastic pollution arguably poses as much of a threat to humanity's survival as climate change. It enters our food and water, and therefore our bodies, and has been linked to diseases from infertility to cancer. Plastic pollution is also clogging up our ocean, with giant piles and random junk alike destroying the lives of millions of sea turtles, seabirds, and marine mammals. The plastic pollution problem is so insidious that so-called microplastic particles have even made their way into our blood. Needless to say, experts agree that the problem is extremely serious and needs to be solved.
This can be achieved by accelerating three key shifts – reuse, recycle, and reorient and diversify – and actions to deal with the legacy of plastic pollution. But experts say the plastic pollution problem may not be intractable. At least that's the conclusion of a recent report from the United Nations. Their analysis claims that the problem of plastic pollution can be ameliorated if human beings act now. The in-depth report lays out methods for managing the massive accumulation of plastic waste on Earth. After all, putting a plug in the deluge of plastics entering our environment every day is only one part of the challenge; the other part is cleaning up the mess that has already been made. The study's authors offer a complex web of solutions that range from regulations on industries that create and use plastics to creating financial incentives for businesses to remove existing plastics in the environment. "The way we produce, use, and dispose of plastics is polluting ecosystems, creating risks for human health, and destabilizing the climate," Inger Andersen, UNEP's executive director, said in a statement. "This report lays out a roadmap to dramatically reduce these risks through adopting a circular approach that keeps plastics out of ecosystems, out of our bodies, and in the economy.”
Andersen added: "Crucially, the report demonstrates that the transformation would provide economic and social wins. Governments and the private sector would save money and hundreds of thousands of new jobs would be created.” One of the primary reasons that experts are concerned about plastic pollution is that many plastic polymers contain chemicals known as "endocrine disruptors". As their name indicates, endocrine disruptors can interfere with the production of hormones in the body. Many endocrine disruptors commonly used in plastic polymers have been linked to precipitously plummeting sperm counts all over the world.
"First society needs to identify and agree we have a very serious problem; this takes time like climate change," Bjorn Beeler, general manager and international coordinator at IPEN — International Pollutants Elimination Network — told media by email. "Scientists knew in the 1970s/80s climate change was coming due to (greenhouse gas) emissions, and now we are discussing adaptation and climate crisis 40+ years later (late). So, to curb the threat, we need to define the problem, then turn off the toxic chemical tap." If rates of human sperm counts continue to fall as they have been over the past few decades, the human species could face a mass infertility crisis by the end of the century. Although it is not confirmed that plastic pollution is entirely responsible for this crisis — other factors from the obesity epidemic to widespread alcohol and drug use may also play a role — many scientists believe it is implicated.
Dr Shanna Swan, a professor of environmental medicine and public health at Mount Sinai School of Medicine in New York City who has been a trailblazer on this issue, explained why for Salon last year. "Chemicals in plastic (phthalates, bisphenols, and others), as well as pesticides, lead, and other environmental exposures, are linked to impaired reproduction including sperm count and quality," Swan explained. "Some, like phthalates and BPA, have a short half-life in the body (4-6 hours), so it is possible to reduce the body's exposure if we can stop using products containing these."
Until the problem is contained, studies indicate that the average human will continue to consume the equivalent of one credit card worth of plastic each week. Most of this is in the form of microplastics, or plastic particles that are five millimeters or less across or in length.
What is microplastic anyway?
A 2020 study found that there may be more microplastics in some waters than zooplankton, a group of plankton that includes tiny animals and some immature larger animals. That may not seem like a big deal, but countless aquatic species rely on zooplankton as a food source; their experience is tantamount to accidentally eating a credit card half the time you try to eat what's on your plate. Indeed, plastic pollution is one of the biggest ongoing threats to the planet, easily on par with climate change and the loss of biodiversity. Plastics are responsible for poisoning our bodies, reducing our fertility rates, and destroying wildlife both on the land and in the sea. Yet plastic pollution does not mean floating bottles and utensils, medical equipment, and random consumer junk. Plastic pollution from these and other goods is broken down in the ocean into tinier and tinier pieces. Much plastic pollution is so tiny that it appears as grains, or perhaps is invisible to the naked eye. These are known as microplastics, and while they are tiny compared to the vast belching smokestacks and mushroom clouds we associate with the most ominous symbols of pollution, microplastics are no less ominous.
What are microplastics?
"A microplastic most typically is defined as a particle that is five millimeters or less across or in length," Rolf Halden, Director of the Biodesign Center for Environmental Health Engineering at Arizona State University, explained. "Even there people disagree, but let's say it's just a diameter of five millimeters or less that makes for a microplastic." Halden says that they are "plastic shavings or debris," which float in the ocean and are created by continually being ground down by the surf. Some microplastics are also remnants of rubber tire shavings that blow off of highways as cars travel — these are rubber polymers. Jacqueline Doremus, an Assistant Professor of Economics at Cal Poly who, among other things, is an expert in evaluating environmental policy effectiveness, explained that the plastic industry itself is connected to the petrochemical manufacturing industry, which plays a big role in pollution. This economic angle explains how plastics have become so pervasive and, as a result, microplastic pollution has become such a major environmental problem. "Plastic is a byproduct of petrochemical manufacturers," Doremus informed by email. "Decreases in demand for oil and gas mean producers betting on plastic. At the same time, more than three-quarters of plastic additives are not disclosed to researchers, the public, or regulators because they are protected as intellectual property or are improperly documented. So, we have two forces at work: strong incentives for a powerful industry to increase plastic production and a poor understanding of the sometimes toxic additives they use."
Where are microplastics?
There is no easy way to answer this question: They are literally everywhere. You cannot escape them. "Microplastics are insidious and now cover large areas of our planet," Mary Crowley, Founder and President of Ocean Voyages Institute, informed. "Besides being found in the deepest part of our ocean, the Mariana Trench, microplastics are also found atop the Rocky Mountains, the Pyrenees Mountains, the Arctic, the Antarctic, and throughout the world's oceans and deserts — everywhere!" Even worse, because plastic is not biodegradable (that is, able to decompose because bacteria or other organisms consume it), it is going to stick around for centuries. "Microplastics end up being ingested by small organisms which are in turn ingested by larger organisms such as fish and birds and via this route, plastic enters into our planet's food web making its way up the food chain," Crowley explained. "Microplastics and larger pieces of plastic are now commonly found filling the stomachs of fish, birds, whales, dolphins, seals and turtles, causing illness and mortality."
Why are microplastics dangerous?
Crowley also elaborated on the ways that microplastics endanger human health. "Microplastics contain toxic chemicals and hormone-altering compounds, which can affect human health in areas ranging from reproduction to immune function," Crowley said. "More studies need to be done for us to begin to gain a full understanding of all the effects microplastics have on human health and the health of our oceans, but from what we can observe, we know plastics are made with substances that are not meant to be ingested. On a macro level, microplastics tamper with the ocean's ability to sequester carbon through plankton, affecting the very air we breathe."
Halden said laypeople may wonder why we make so many products out of plastic if it is toxic or hazardous to human health. "The answer to that is that, historically, we have made choices to enough of the ingredients to make plastics that in hindsight turned out to be very poor ones," Halden explained. One example is vinyl chloride, which scientists later learned is a potent carcinogen. "If you look to food, we don't use PVC (polyvinyl chloride, a polymer of vinyl chloride) to package food," Halden said. "We use polyethylene and other polymers, right? And they are initially safe for the purpose they're intended for. However, since we make so much of it and it gets out into the environment, then it grinds down. They are changing their chemical makeup and their physical appearance and they become a health hazard."
To illustrate the processes at work here, Halden suggested that people imagine a disposable plastic yogurt cup. Once they eat the yogurt, they throw away the cup. What happens to it? The chances are pretty good that, eventually, it will find its way into a body of water like the ocean or a river. "It floats there for a long period of time and can absorb a lot of air and water pollutants," Halden explained. "It becomes like a toxic float and its surface characteristics can change so it almost looks like a piece of asbestos. And we know that foreign particles that get into our lungs or other organs can cause inflammation and cancer. So the material changes over time and with it, the risk, and that is something that is not intuitively understandable by a lay person when they evaluate plastics and wonder, 'Should I buy more plastics? Am I doing the right thing here? Or should I change my, my behavior?'"
How can we protect ourselves from microplastics?
Lisa Erdle is the Manager of Science & Innovation at 5 Gyres, a nonprofit devoted to fighting plastic pollution. "Once microplastics are in the environment, they are nearly impossible to clean up," Erdle informed via email. "There have been some technologies designed to 'clean up' the ocean, for example, but these are expensive, have other negative impacts on the environment, and are exceedingly difficult to implement at scale. However, other technologies, like those that capture microplastics closer to the source, are effective at capturing microplastics before they enter the environment." One example of this is washing machine filters that capture microfibers before they can infiltrate aquatic environments; another is storm drain traps that capture plastics on our roads before they enter bodies of water. "Since there are many different sources of microplastics to the environment, it is likely we will need a range of different solutions to prevent their emissions to the environment," Erdle observed.
Should manufacturers be held responsible?
The problem boils down to rights. Who has the right – companies to produce plastic without consequences? Or do people have a threshold of plastic they can expect in the air we breathe and the water we drink? From this vantage point, there are several approaches including taxing plastic, reclassifying it as a pollutant so it can be regulated, and forcing companies to "take back" their plastics. On an individual level, people can change their lifestyles to reduce their plastic output. Wash your clothes less and line dry, this avoids microfiber pollution and carbon emissions – win-win. Same with carpooling and reducing driving, which reduces tire fibers, carbon emissions, and local pollutants that increase asthma. If you smoke cigarettes, be careful to dispose of the butts in the trash, as they contain highly toxic microfibers. Avoid plastic bottled beverages, as the manufacturing process likely introduces microplastic. Reduce your use of plastic where you can. Start with small measures and be kind to yourself if you can't avoid it. It's not you – it's us!
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