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Are biodegradable bags better than plastic? It's complicated.

I used to transport bins of coffee grinds, plant trimmings, and fruit and vegetable trash to the student farm's 50-foot-long compost pile by driving a small electric truck around campus. Although we requested that no post-consumer waste be placed in the bins at our pick-up locations, "compostable" plates, cups, and bags unavoidably ended up in our pile. When they did, I would take them out and discard them in the garbage.


Labels like "biodegradable" or "compostable" have this drawback. These goods eventually biodegrade, which means that microorganisms and other organisms break the components down into the soil. They are primarily created from plant sources, frequently corn. But it matters where the items are disposed of. The "compostable" bags and "biodegradable" cups remained, fully intact, as the banana peels and straw turned into crumbly compost. If they had been delivered to a large-scale, industrial recycler, where staff members control the environment and the chemistry of the materials to ensure the frenetic action of millions of bacteria capable of dissolving these hard materials, they would have decomposed. And this? Not for a long time, if ever.


Researchers from the University of Plymouth published a report on Sunday addressing the issue of unclear labelling. In soil, outdoor air, and marine water, the researchers examined the degradability of numerous bioplastic bags—some of which had labels like "biodegradable" and "compostable"—as well as traditional high-density polyethene (read: plastic) bags. All but the biodegradable bag were still able to carry a load of goods after three years in water and soil. After 27 months underground, it was still present but easily torn apart.


Imogen Napper, the primary author and a marine scientist, believes that "in day-to-day living, [these labels] are deceptive." Although most of the materials aren't going into an industrial composter, that is where they are intended to go. According to Napper, the labels mislead consumers into believing that the products decompose quickly in situations like the ones she investigated when in fact it can take years for a product to reach the soil. What is the time range that comes to mind for a product in the natural environment when it states it is biodegradable or compostable, she asks. "It would take days to months for me. When you start to say two to three years, does the environment gain anything substantial from that? I contend not.


This attitude has been mirrored in headlines about the study, including Vice's "Biodegradable Plastic Bags Aren't Better For The Environment." The majority of the reports emphasised how the biodegradable bags could still transport groceries three years after being buried. Even if that conclusion is concerning, the truth is a little bit more nuanced.


The distinction between labels is where it all begins. The terms "biodegradable" and "compostable" should, in theory, represent the same thing: that a product can be broken down by soil-based organisms. However, according to Kate Bailey, policy and research director at Eco-Cycle, a nonprofit recycling organisation, "biodegradable" actually provides you with the same amount of information as the term "natural" on a food item does. Biodegradable merely indicates that the product will decompose at some indeterminate point in the future—months, years, decades, who knows!


In keeping with the food comparison, the term "compostable" is more akin to "organic," in that regulators are attempting to guarantee it complies with specific requirements, albeit what those requirements are is still under development. When a product is marked as "certified compostable," it signifies that it will break down into compost at an industrial facility in roughly the same amount of time as other materials in the pile, such as food scraps and grass clippings—typically between 90 and 180 days. This has been independently verified by a few organisations, including ASTM International, which creates standards for hundreds of goods and services. The idea that a label "has to symbolise something" and can't simply be tossed out there to confuse customers is undoubtedly gaining ground, according to Bailey.


But Bailey continues, "the phrase "biodegradable" still makes composters anxious. There is a great deal of worry about the labelling, she continues. "Composters want everything to be certified compostable; they don't like biodegradable," Biodegradable is essentially just another "greenwashed" term that businesses use to make us feel good about making an expensive purchase, even if its environmental advantage isn't actually obvious.


A few organisations are acting. In its most recent "Green Guides," the Federal Trade Commission states that "degradable claims" must be supported by "competent and reliable scientific evidence" demonstrating that the entire item will completely "decompose into elements found in nature within a reasonably short period after customary disposal." California is also strictly enforcing laws against decomposition fraud. The sale of goods advertised as "biodegradable," "compostable," etc. is prohibited by law unless there is supporting documentation. Following a lawsuit filed by district attorneys against Amazon for selling goods with deceptive labelling, including "biodegradable," the Golden State will get $1.5 million as part of the settlement.


By this point, you may be thinking if it's all a waste of money to use eco-friendly office supplies or the tiny green bags you use to line the compost bucket on your kitchen counter. Great if your city, like San Francisco, Seattle, and Portland, collaborates with a composter! These items can be used in a specific location to turn into soil.


Simply check the label again. Bailey advises customers to look for certified biodegradable labels.


But what if you're one of the roughly 95% of homes without access to such a service? A product could not be superior to plastic even though it is "certified biodegradable." Currently, a lot of compostable bags, cups, and footwear are made from corn, which has a variety of negative effects on the environment, from pesticides that seep into rivers to greenhouse gases emitted by the plants that make the products. There is great hope for producing compostable plastic from materials like hemp, algae, or mushrooms, which could be much more advantageous than plastic, says Bailey. But as of now, "it's not apparent that there is much of a benefit [compared to plastic], with most things originating from grain."


This is supported by research from the Oregon Department of Environment Quality. Researchers looked examined earlier analyses of the life cycles of various "packaging attributes"—labels like "recycled content," "biobased," and our good pal "compostable." Each study examined how the product affected the environment at every stage of its "life," from production to disposal. The investigation came to the conclusion that biodegradable goods are not a simple replacement for plastics. According to the authors, a lot of biodegradable packaging is comprised of biobased materials and carries a heavy environmental cost associated with its production. "These costs are frequently significantly more than the benefits that composting offsets."


The manufacture of these greenwashed items is mostly responsible for their negative environmental effects. 39% of our domestic greenhouse gas emissions occur before a product even reaches a consumer, while only 2%of GHG emissions arise from disposal (landfill, composting, and incineration), according to a brochure for the study.


However, whether it be a landfill, recycler, or compost pile, these life cycle analyses mainly neglect what occurs when a product doesn't follow its recommended disposal route. But every year, a lot of plastic goes astray.


According to one estimate, between 4.8 and 12.7 million metric tonnes of plastic waste entered the ocean in 2010. Additionally, when plastic is left in the environment, it just fragments into smaller and smaller pieces with the same chemical makeup rather than decomposing. These tiny plastic particles are a problem because they are nearly impossible to remove, are consumed by marine life, end up in the seafood we eat, and ultimately end up inside our bodies.


When it comes to reducing the plastic crisis in the ocean, compostable items may have an advantage. Compostable bags were found to degrade in seawater after three months in a University of Plymouth study.


Therefore, even if they might not be advantageous from the standpoint of the life cycle, they might be less detrimental to marine creatures.


There is one obvious method to win on all environmental fronts, even though there are numerous ways to compare the effects of conventional plastic and biodegradable alternatives. You've heard it before: reduce your usage of plastic, especially for one-time use, and you'll use fewer resources and leave less litter behind.


However, Bailey advises that "more clear labelling rules [for compostable products] are a fantastic starting step" in cases where it is impossible to avoid using disposable bags, cups, or plates.


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