According to a report from the European Commission, one hundred billion plastic bags are sold in the European Union each year with around 8 billion of these ending up as litter. Labeling them as biodegradable does not change this. It does not significantly decrease the volume of plastic entering the ocean or the physical and chemical risks that plastics pose to marine environments, explains a United Nations report.
Regarding plastic bags, the term “biodegradable” can be misleading. There is no indication as to how long the material takes to degrade, or under what conditions. The only thing bio about them is that they can be made from bioplastics – plastics made from renewable biomass sources such as corn, algae, or chitin – or from petrochemicals that have added elements that help them biodegrade.
However, this does not make them good for the environment. In a way, it makes them worse because calling them biodegradable makes it seem like they are ok for the environment. People even think there’s nothing wrong with littering and throwing these bags into the wild or in the ocean. In addition, labeling a product as biodegradable may be seen as a technical fix that removes responsibility from the individual, resulting in a reluctance to take action.
The reality is, research has found that a “biodegradable” bag can still carry a load full of shopping even after 3 years of being buried underground! Not only that but when they do start to degrade, they break apart into small pieces and pollute the soil and waterways as microplastics.
Architect and recycling expert Arthur Huang told Dezeen:
If we use them the same way [as conventional plastics] they are just as bad if not worse. They change the pH value of soil and water as they degrade, and they take away valuable food supplies.
Most of the bags require very specific conditions to actually degrade. For example, some polymers require industrial composters and prolonged temperatures of above 50°C to disintegrate. Such conditions are rarely if ever met out in the environment. When they do disintegrate, the plastic does not go away but breaks down into microplastic particles. These microplastic particles are then ingested by marine organisms and they also facilitate the transport of harmful microbes, pathogens, and algal species.
Oxo-biodegradable plastics break down into microplastic particles that are usually too small to see and pollute everything. Microplastics have been found in the air, the ocean, rivers, at the top of mountains, in microorganisms, animals, and in the human body. They’ve also been found in our drinking water, beer, and foods.
Testing
The University of Plymouth’s International Marine Litter Research Unit conducted a study to challenge the assumption that switching to biodegradable plastics could reduce ocean-plastic pollution. They published the study in the Journal of Environmental Science and Technology.
Imogen Napper, who co-authored the report, said: “Our results showed that none of the bags could be relied upon to show any substantial deterioration over a three-year period.”
A spokesperson for Vegware, the company whose compostable bags were used for the research said:
University of Plymouth’s research is a timely reminder that no material is magic, and can only be recycled in its correct facility.
The experiment involved testing out five types of plastic carrier bags, all widely available on the UK high street. They included a biodegradable bag, an oxo-biodegradable bag, and a compostable bag, as well as a standard plastic bag made of high-density polyethylene. They were all tested under conditions they’d encounter if discarded as litter. The conditions included being left in the open air, buried under soil, or submerged in the sea.
The scientists tested the bags at regular intervals. They monitored them for changes in strength, texture, and chemical structure. The results after three years in the soil or a marine environment were shocking – the biodegradable bag, the oxo-biodegradable bag, and the standard plastic bag remained fully functional. The compostable bag worked best as it did disappear in the sea after just three months, but was still present in the soil when tested after 27 months – however, unable to hold a load without ripping. Lastly, all of the five kinds of bags broke down into fragments within nine months when exposed to the air.
Richard Thompson, who heads the unit that conducted the research, said:
This research raises a number of questions about what the public might expect when they see something labeled as biodegradable. We demonstrate here that the materials tested did not present any consistent, reliable and relevant advantage in the context of marine litter. It concerns me that these novel materials also present challenges in recycling, since biodegradable plastics need to be recycled separately from conventional plastics.
Napper added:
After three years, I was really amazed that any of the bags could still hold a load of shopping. For a biodegradable bag to be able to do that was the most surprising. When you see something labeled in that way, I think you automatically assume it will degrade more quickly than conventional bags. But, after three years at least, our research shows that might not be the case.
What Can I Do?
It’s good to recycle plastic when possible. However, it isn’t a perfect solution; plastics are typically recycled into lower-quality plastics, and not all plastics are recyclable, this includes plastic bags. Plastic bags often cause problems with machines at recycling facilities, resulting in them being shut down regularly to unclog them. Many people put their recycling plastics into plastic bags for collection, but this can actually result in the bag and the plastics within it all going to landfill.
A lot of recycling plastic also gets shipped overseas to poorer countries where it covers beaches and rivers. The majority of the plastic in the ocean comes from these rivers. Many countries have signed a United Nations agreement to stop shipping waste to poorer countries. The United States is one of the few countries that didn’t sign the agreement. Some nations such as China have restricted waste imports, this has led to a lot of recycling waste being incinerated, polluting the air.
What’s the solution? On an industrial scale, more research needs to be done to create materials that degrade faster, but also materials that degrade entirely, unlike oxo-biodegradable plastics which break down into microplastics. Compostable materials are better than biodegradable ones, but they still require optimum conditions to break down quickly.
The best thing to do when it comes to plastic bags is to reuse them, that way they don’t become waste at all. The other thing we should all try to do is use less single-use plastics.
