Are Compostable Bags As Environmentally Friendly As We Think They Are?

Bin with compost items and suggestions on what to do with paper and compostable bags, Union Square ... [+] Farmer's Market, New York City. (Photo by: Joan Slatkin/UCG/Universal Images Group via Getty Images)

Walk into any supermarket or retail store and the chances are you will see a variety of bags and packaging marked as compostable.

For eco-friendly shoppers the world over, this can only be a good thing. After all, we all know that single-use plastics are the scourge of the environment, and to be avoided at all costs.

But are many of the items being branded as compostable actually good for the environment? Or is it the case that many of us are using them incorrectly? Perhaps we assume they are home compostable, when the reality is they are only compostable in larger facilities. And do they really harmlessly break down, or is this another example of greenwashing in action?

According to research conducted by packaging platform Sourceful, only 3% of compostable packaging in the U.K. ends up in a proper composting facility.

Instead, it claimed a lack of composting infrastructure means 54% goes to landfill and the remaining 43% gets incinerated.

Sourceful’s CEO and co-founder, Wing Chan, said the practical reality of compostables “does not reflect the narrative used to market them”.

“We recommend avoiding and looking to switch out where possible in your supply chain,” added Chan.

Dr. Tarun Anumol, from Agilent Technologies, said plastic bags are commonly made from the polymer polyethylene, which depending on the conditions can take up to 1,000 years to fully break down in the soil.

And when they do start to disintegrate, Anumol added they can frequently break down into micro-plastics, which research shows can contaminate the soil, be absorbed into crops or pollute nearby water streams.

Once in the water supply or food chain, they can then be ingested by humans and enter the bloodstream.

In addition, he said microplastics can also attach to other pollutants and even increase the toxicity of other substances in the soil, like chromium and other organic pollutants.

In terms of compostable bags, he said many of them take between 10 and 60 days to degrade in the soil, depending on favorable environment conditions.

He said in some instances, home composting does not necessarily provide the right environmental conditions for decomposition, so the bags may “stick around for a lot longer” but still not as long as traditional plastics.

Anumol said it was important that the right disposal systems are in place to manage compostable bags, but he added this is really a “teething issue” that will be sorted out over the next few years.

But he said it was still vital that soil is regularly tested and analysed for possible contaminants to ensure safe and fertile soil.

Sarah Paiji Yoo, the CEO and co-founder of the eco-friendly cleaning product firm Blueland said ultimately, she believes compostable bags are still better than virgin plastic bags, because they are not made with petroleum-based plastic.

But she added compostable bags need to be industrially composted to truly effectively degrade.

“Compostable bags that are put in the trash can last in a landfill for tens and hundreds of years since objects in landfills,” she added.

The CEO of plant-based fiber packaging manufacturer Footprint, Troy Swope said he believes we are “not quite there yet” with compostable bioplastics.

“When we started Footprint, we considered bioplastics, but ultimately we found the best solution for the planet was a nature-based solution,” Swope told Forbes.

Swope said they use recycled cardboard, paper and other natural substances, like algae to develop a fiber, which in turn, can be used to create biodegradable packaging.

“We want solutions that nature can digest, so that if it got into a river and into your ocean, it would break down will not harm sea life,” he added.

And Graham Rihn, founder and CEO of the waste management platform RoadRunner Recycling, said it was important to draw a distinction between biodegradable bag liners and compostable liners, which he added are designed for a very specific function.

Ultimately, he said if there is compost service available, then “you should absolutely use compostable products, if at all possible”, because it will leave a far smaller footprint on the environment than the alternative.