Why biodegradable bags accelerate pollution of the planet

Since sustainability became a trend, many companies have emerged producing “bio-bags” and “eco-bags” instead of polyethylene. However, not all of them meet environmental standards. To understand whether alternative plastics are beneficial for the environment, let’s clarify the terminology.

Bioplastic does not mean environmentally friendly

Bioplastics are biologically based plastics. This material is made from biomass (corn, straw, sawdust), rather than fossil fuels  —  an advantage over conventional plastics made from petroleum.

Photo: Henry Be / Unsplash

There are many bioplastic bags on the market, and manufacturers claim their products are environmentally friendly due to their natural ingredients. However, they fail to mention that bioplastics decompose in the environment at the same rate as plastics. This means that any plastic can be considered biodegradable, as it will eventually decompose after several hundred years. The only difference is that bioplastics will release methane, a greenhouse gas that exacerbates the climate crisis, while conventional plastics will decompose into microplastics, which pollute soil and water bodies.

Biodegradable plastic is better, but it’s not that simple

Biodegradable plastics do, in fact, completely decompose over time. The catch is that products made from biodegradable plastic don’t specify how long it will take or under what environmental conditions. Most people interpret the term “biodegradable” as meaning “bury it in the garden or throw it in the ocean, it will completely decompose.” But in reality, most biodegradable plastics can only decompose in a special industrial facility where temperature, humidity, and light are controlled.

Biodegradable plastics include oxo-degradable, hydrodegradable, and compostable plastics, which “dissolve” when exposed to oxygen, water, or bacteria.

Biodegradable plastics labeled as compostable are only composted in industrial facilities, not at home.

Oxo-degradable bags cannot be sent to landfills. When exposed to oxygen, such a bag will simply break down into microplastics, and the additives responsible for oxo-degradation are potentially toxic. So toxic that, due to their harmful environmental impact, the European Commission recommended in January 2018 banning the use of oxo-degradable plastics in the European Union.

Photo: Guillaume Périgois / Unsplash

In the worst-case scenario, manufacturers label plastic bags “biodegradable” with special additives that accelerate their decomposition into microplastics. In such cases, labels like “safe for the environment” and “environmentally friendly” on packaging and bags should be taken in quotation marks.

Which bags should I use?

Unfortunately, even reading tons of reference material and understanding the recycling processes for each type of plastic won’t help answer this question. Bag manufacturers rarely list their products’ ingredients, and waste collection points don’t accept biodegradable bags because they lack the necessary infrastructure.

The complexity of recycling all biodegradable materials is most clearly demonstrated by a study conducted by scientists from the University of Plymouth in the UK. In this study, biodegradable, oxo-biodegradable, compostable, and polyethylene bags were exposed to different environmental conditions for three years: left outdoors, buried in soil, submerged in water, and tested under controlled laboratory conditions.

Photo: University of Plymouth

When exposed to open air, all the bags disintegrated into fragments after nine months, while those immersed in soil and salt water showed virtually no effect. Only the compostable bag completely dissolved in water after three months, but survived in soil for 27 months. Biodegradable and oxo-biodegradable bags retained their strength even after three years. The experiment showed that none of the bags disappeared without a trace; no magical decomposition occurred  —  even the decomposed bags left behind particles.

Biodegradable materials can only decompose through industrial recycling. In the natural environment, this requires exposure to microbes, oxygen, humidity, and other factors that cannot be replicated in everyday life.

In countries without developed infrastructure to ensure proper disposal of biodegradable materials, the introduction of compostable and biodegradable bags could increase plastic pollution.

The environmental think tank Green Alliance noted that the term “biodegradable” leads consumers to believe that the bag can be discarded with a clear conscience, which would further pollute the environment.

Photo: Pexels

Ultimately, it makes no difference whether you carry your groceries home or throw out your trash in a biodegradable trash bag or a plastic one. In everyday life, biodegradable bags are no better than regular plastic ones, and stores set their prices two to three times higher, expecting us to pay more for preserving our planet.

Currently, the only environmentally friendly solution, the best alternative, is to reduce the use of plastic packaging rather than replace it with other materials.

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