Are biodegradable plastics really a thing?

On the surface, biodegradable plastic is a miracle. It looks like plastic and acts like plastic. And it will return to nature after you throw it away.

But there’s a big catch: Just because your fork, plastic cup, or dog poop bag is marketed as biodegradable, that doesn’t necessarily mean it will decompose in the environment. The same thing happens with so-called compostable plastics. Here’s why.

Many biodegradable plastics can actually decompose, but only under certain conditions. One of the most common compounds is a polyester called PLA, short for polylactic acid, which will biodegrade in industrial compost environments.

But most places in the United States do not make industrial fertilizers. That means discarded PLA will most likely end up in landfills, rivers, or oceans. It can even be burned, releasing planet-warming gases and toxic chemicals into the environment.

Furthermore, most curbside recycling programs cannot recycle biodegradable plastics, including PLA. If people throw them in the recycling bin, they can contaminate the plastic that actually belongs in that bin. And that gives recyclers a headache in sorting.

(And as for dog poop bags, remember that many commercial composters do not accept pet waste. That’s one reason the Federal Trade Commission issues warnings that manufacturers dog poop bags make “biodegradable” claims could be a lie.)

“This is complicated because biodegradability varies depending on the environment,” said George W. Huber, a chemical engineering professor at the University of Wisconsin-Madison who researches solutions for plastic waste. depends on where you are and what happens to your plastic.” “And there are companies that make claims about biodegradable plastics that are not supported.”

That kind of misinformation doesn’t just mean people may have to pay more for things that don’t help the environment as much as they think, he said. It can also create more consumption and waste, if people believe they can buy as much biodegradable plastic as they want without much impact on the planet.

Maybe worse, it can also make people feel like they can throw their trash anywhere because they think biodegradable plastic will return to nature on its own. (Again, that won’t happen. So please don’t litter!)

Of course, the crux of the problem is that the world is drowning in plastic.

According to the United Nations Environment Program, the world produces 430 million tons plastic a year, more total weight of all humans. UNEP estimates that only 9% of plastic waste is recycled. And conventional plastic, made from fossil fuels, takes centuries to decompose.

Biodegradable plastics are a promising solution, and scientists around the world are researching new types. For example, Dr. Huber’s team in Wisconsin has developed a new plastic made from corncobs that is easily biodegradable and has the potential to replace polyethylene, which is widely used for packaging. However, reducing production costs remains a challenge.

Ruihong Zhang, a professor of biological and agricultural engineering at the University of California, Davis, thinks the world may soon have biodegradable plastic. She is researching a type of plastic made from cheese waste by-product Biodegrades more easily in the environment.

That will not only reduce the amount of plastic waste sent to landfills. Producing plastic from food waste would also produce fewer planet-warming emissions. “We are basically trying to solve the waste problem and reduce emissions at the same time,” Dr. Zhang said.

So, if you want to minimize your environmental impact, what can you do to navigate the difficult world of biodegradable plastics?

First, you can get acquainted with the main types of biodegradable plastics. And before you buy any plastic advertised as biodegradable, check what type of plastic it actually is and what conditions it needs to actually biodegrade.

The nova Institute, an independent research organization in Germany specializing in plastic solutions, has a helpful graphic divided into several main categories. It also tells you whether they have proven to be biodegradable – in soil, in landfill, in fresh water or at sea – or whether they require more specialized treatment such as a composter. industrial fertilizer or anaerobic digester or not.

Then, if biodegradable plastic doesn’t meet your needs, you can use recyclable plastic instead. (But remember Recycling comes with its own challenges.)

And ask yourself: Are there non-plastic alternatives to what you need that are reusable or made from truly biodegradable materials like paper?

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