12/5/2023 0 Comments Does plastic break down![]() But he’s not surprised the bags didn’t decay completely. ![]() Animals even mistake these tiny pieces for food.Ĭhemist Marty Mulvihill says he’s “a little surprised” that most of the bags could still hold groceries after three years. These bits - each smaller than a rice grain - can spread easily through the environment. But any chunks not eaten can further break apart into microplastics. It may make the plastic easier for microbes to digest. This breaking of plastic into smaller fragments may be a good starting point, he says. Bags marked “compostable” were the only ones that disappeared completely. Even after three years in such environments, three of the four types of biodegradable bags could still hold up to 2.25 kilograms (5 pounds) of groceries. Most of the bags didn’t break down much in soil or seawater. At the end, they measured how well the plastic had broken down. For three long years they observed what happened to these bags. They placed still more of them in a closed, dark box in the laboratory. They tied others to a wall where the bags could flutter in the breeze. They buried some of each type in garden soil. ![]() For the tests, they submerged some bags of each type in ocean water. They would compare these to a group of ordinary plastic bags. The pair chose bags made from each of four different types of biodegradable plastic. To study how well these bags live up to such claims, Thompson and Napper collected 80 single-use plastic bags from stores for testing. Some plastics may even need special conditions - such as heat - to fully break down. There’s also no one rule for how quickly biodegradable plastic bags should break down. Others may be held together with chemical bonds that break apart when exposed to water or sunlight. So these plastics don’t decay easily.īiodegradable plastics are sometimes made from materials that microbes do readily digest. The problem: Ordinary plastic bags are made from oil, which few microbes can digest. Other living things can now feed on these breakdown products to grow. That’s usually a process whereby microbes feed on them, breaking big molecules into smaller, simpler ones (such as carbon dioxide and water). Materials break down through rot or decay. Thompson and a graduate student, Imogen Napper, decided to test that. He’s a marine biologist at the University of Plymouth in England. We wanted to test whether biodegradable plastic bags could help reduce plastic pollution,” says Richard Thompson. “Single-use plastic bags are a huge source of litter worldwide. ![]() But a new study in England shows that may not happen. These are supposed to break down faster than regular plastics. That’s one reason some companies have switched to biodegradable plastic. Some of these bags end up as litter that may harm animals (including those in the ocean). As the plastic is tossed around, much of it breaks into tiny pieces, called microplastics.Plastic bags are handy for carrying light items. Some plastics float once they enter the ocean, though not all do. That means plastic can stick around indefinitely, wreaking havoc on marine ecosystems. Unlike some other kinds of waste, plastic doesn’t decompose. If this waste isn’t properly disposed of or managed, it can end up in the ocean. Many plastic products are single-use items that are designed to be thrown out, like water bottles or take out containers. Just think about all the plastic items you use daily: the toothbrush you grab first thing in the morning, the container your lunch comes in, or the bottle you drink water from after your workout.Īll these things get used and, eventually, thrown out. These plastics come in many different forms. That’s the weight of nearly 90 aircraft carriers, and the problem continues to grow. While it’s tough to say exactly how much plastic is in the ocean, scientists think about 8 million metric tons of plastic entered the ocean in 2010.
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