A team of British scientists has been testing biodegradable plastic bags, that can now be found in the majority of big supermarkets. However, it seems that biodegradable plastic bags aren’t actually biodegradable. Let’s explain.
Over recent years, biodegradable plastic bags have been popping up in lots of big supermarkets. Sold as a ‘green’ alternative to classic plastic bags, for many, they have become an interesting option since recent legislations have banned single-use plastic bags.
But are these plastic bags actually biodegradable? According to a recent scientific study, the answer is unfortunately, no. For three years, researchers at the University of Plymouth have been testing these supposedly biodegradable bags and their findings were recently published in the Environmental Science & Technology magazine.
Almost completely intact
For three years, they gave different types of bags time to decompose, some of them in a marine setting, others in soil and others in the open air. Their goal was to measure the natural degradation of these plastic bags. They tested five different types of bags: one biodegradable, one compostable, one so-called ‘classic’ bag, with a strong concentration of polyethylene and two oxo-degradable bags. Although oxo-degradable bags are prohibited in some countries, they are still largely used around the world.
Over these three years, this is what the scientists observed. The majority of these bags remained intact, and still solid enough to carry objects. Only the compostable bags were dug up in relatively good condition but couldn’t carry any weight. Those that were placed in a marine setting had completely disappeared after 27 months. Whilst the results are hopeful, researchers also say that it still remains to be seen whether decomposition of these materials is completely safe for the environment.
Reducing single use
‘When you see something labelled 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,’ insists Dr. Imagen Napper, the main author of the study.
Despite their promises, these bags do provide a reliable alternative to classic plastic bags.
‘Discarding a product in the environment is still littering, compostable or otherwise,’ explains researchers. However, scientists highlight that half of these bags, whether sold as ‘green’ or not, are almost always thrown away after just one use. Therefore, they too end up representing quite a large quantity of our waste.