top of page

Do ‘Biodegradable’ Plastic Bags Actually Degrade?

There is no denying that plastic bags cause pollution in the world. Each year, 100 billion single-use plastic bags are used in the United States alone; another 100 billion bags are used in the European Union. These bags frequently find up in the environment, where they endanger wildlife. Standard plastic bags don't decompose; instead, they disintegrate into minute bits that are eaten by a variety of creatures and move up the food chain.

Given these depressing facts, biodegradable plastic bags have been promoted as a superior method of transporting groceries and other retail goods home. However, a recent study suggests that biodegradable bags may not truly break down all that quickly in the environment, as Laura Parker of National Geographic explains. In fact, after three years of exposure to the weather, some could still carry almost five pounds of food.

The study, which was written up in the journal Environmental Science & Technology, details an investigation conducted by University of Plymouth scientists who wanted to see how five different plastics behaved over time in varied conditions. Imogen Napper, a research associate, and Richard Thompson, a marine biologist and the director of the university's International Marine Litter Research Unit, tested various types of plastic bags, including common ones, compostable ones, biodegradable ones, and two kinds of oxo-biodegradable ones.

Since these bags do not require microorganisms to break down, they "should biodegrade predictably in any environment," according to Mark Wilson of Fast Company.

Each sort of bag was fastened to a wall exposed to the sun, buried in a university garden, sunk in Plymouth Harbor, and, for control, kept in a lab's black box. Both full bags and bags that had been cut into strips and placed within mesh pouches were tested by the researchers. The experiment started in July 2015, and the scientists routinely checked on the bags.

The compostable bag entirely broke down in the maritime environment after three months, but it was the only bag to do so. The open-air bags were all reduced to pieces after nine months. Even though it was too feeble to support any weight, the biodegradable bag in the soil continued to maintain its shape after 27 months. The biodegradable, oxo-biodegradable, and conventional plastic bags maintained a considerable portion of their original shapes after three years in water and soil. The bags were still usable, which meant that they could hold groceries without breaking, which surprised the researchers greatly.

According to Napper, "I was extremely shocked that any of the bags could still handle a load of groceries." The ability of a biodegradable bag to achieve that surprised me the most. I believe you instinctively presume something will degrade faster than regular bags when it is labelled that way. However, our research indicates that might not be the case after at least three years.

According to the researchers' report, the experiment's findings make them wonder whether "the oxo-biodegradable or biodegradable formulations give sufficiently advanced rates of deterioration to be helpful in the context of reducing marine litter, compared to traditional bags."

However, some detractors have noted that compostable, oxo-biodegradable, and biodegradable bags are not designed to decompose in every environment. Compostable bags are intended to be discarded in commercial composters, according to Ramani Narayan, a chemical engineer at Michigan State University who was not engaged in the study. One of the oxo-biodegradable bags used in the study was created by Symphony Environmental Technologies, and the company claims that its products are designed to break down on open land or ocean surfaces rather than in deep landfills or oceans.

It's yet unclear, according to the researchers, whether allegedly biodegradable bags disintegrate any quicker than regular plastic bags. The experts emphasise the significance of giving consumers clear instructions on how to properly discard these products because biodegradable and compostable bags are frequently incompatible with recycling infrastructure. According to Thompson, "our work highlights the necessity for guidelines relating to degradable materials, precisely defining the acceptable disposal strategy and rates of degradation that can be predicted."

Making the most of plastic bags' durability by reusing them several times could be one method to mitigate the harmful impacts of their persistence in the environment. "Perhaps durability in the form of a bag that can and is reused many times presents a preferable alternative to degradability," the study's authors conclude.

How Exactly Do Your Checked Bags Board the Plane?

Typically, your luggage travels with you. However, before they've even boarded, they have a six-mile automated journey through the airport's underground.

3 views0 comments

Recent Posts

See All


bottom of page