Are bioplastics better for the environment than conventional plastics?

Confusion among terms like bioplastics, bio-based and biodegradable plastics makes it hard to discern – and make – the environmentally responsible choice.

Have you ever stood in front of a supermarket shelf and wondered if you should buy that product made from bioplastics rather than the conventional kind? Many people assume all bioplastics are made from plants and can break down completely in the environment. But that’s not the case.

The term “bioplastics” is actually used for two separate things: bio-based plastics (plastics made at least partly from biological matter) and biodegradable plastics (plastics that can be completely broken down by microbes in a reasonable timeframe, given specific conditions). Not all bio-based plastics are biodegradable, and not all biodegradable plastics are bio-based. And even biodegradable plastics might not biodegrade in every environment. Sounds confusing? It certainly is.

“There are a lot of bioplastics or materials that are called bioplastics that are not biodegradable,” says Constance Ißbrücker, head of environmental affairs at the industry association European Bioplastics.

For some plastics, the same polymer chains can be made from renewable sources. The resulting bioplastics are chemically identical to their fossil counterparts. PET, for example — short for polyethylene terephthalate, which is the stuff most bottles are made of — can be synthesized from fossil fuel products or plants like sugarcane. The resulting material is the exact same. Such non-biodegradable bioplastics behave in the environment just like conventional plastic and persist for an unknown but long amount of time.

Not only that, but none of the standards for plastics labelled as biodegradable or compostable today makes them suitable for disposal in the open environment. Given that, can bioplastics play a role in tackling environmental problems? Or are they merely greenwashing? The most accurate answer is, it depends.

Tackling confusion

There’s no doubt, bioplastics are still plastics. Just because some of them are made from plants or have the potential to biodegrade under limited conditions, they can’t be touted as “planet-safe.” For the ones that claim to biodegrade or compost, the fine print is crucial.

So check the label: What does it say? Where and how is it supposed to biodegrade? How can you safely dispose of the product? 

Finally, be cautious when you read that a material is oxo-biodegradable*. These are conventional plastics like polyethylene mixed with metal compounds that make them fall apart faster. According to a report by the United Nations Environment Programme (UNEP), it hasn’t been proven that they truly biodegrade, and it is feared they might just accelerate microplastic pollution. Similarly, European Bioplastics warn that so-called “enzyme-mediated degradable plastics” aren’t truly biodegradable.

Reduction remains key

There’s no doubt, bioplastics are still plastics. Just because some are made from plants or have the potential to biodegrade under limited conditions, they can’t be touted as “planet-safe.” For the ones that claim to biodegrade or compost, the fine print is crucial. 

The plastic industry projects strong growth in production, and biodegradable plastics won’t solve the plastic crisis, so tackling consumption remains key. “By just reducing the amounts and the types of different packaging that we have in our supermarkets, we can do a lot, without developing novel materials,” says Wurm.

Even European Bioplastics’ Ißbrücker thinks that might very well happen. “Maybe not in 5 or 10 years, but as the problems keep growing, plastic production might go down one day, because it’s just too much.”

This article is a highly condensed version of the original, by Anja Krieger, published 16 July 2019 and available online at Ensia ensia.com/features/bioplastics-bio-based-biodegradable-environment

*Plastic bags that biodegrade to nothing?

A British company which makes what are called “Oxo-biodegradable” bags says they break down in the environment “like a leaf, only quicker”, and the technology is being widely used across Africa and the Middle East. So if they are that good, why are they facing a possible ban by the European Commission?

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