Push on the unnecessary use of plastic with a & # 39 is a noble and necessary one, but a new study casts doubt on how eco some form of biodegradable plastic in fact.
The researchers found that the bags are labeled biodegradable and compost were still able to carry the full load of shopping after a left to degrade in the elements for three years – they do not break down almost as fast as you would expect.
The question raised by the study from the University of Plymouth in the UK, or & # 39 is a biodegradable chemical mixtures in these bags very far. If the plastic is still in the environment three years after they are removed, so far the main litter and pollution problem that needs a solution.
"After three years, I was very surprised that any of the bags can still keep buying the load," said lead researcher Imogen Napper. "For biodegradable bag to be able to do it was the strangest thing."
"If you see something labeled in such a way, I think you automatically assume that it will degrade faster than conventional bags. But after three years, at least, our research suggests that may not be so. "
Team tested five different types of plastic bag material in general, all widely available in the UK retail: two types of oxo-biodegradable bags, a biodegradable bag, a compost bag, and a conventional high density polyethylene plastic bag.
Oxo-biodegradable plastics are broken down into fragments relatively quickly, but can still leave behind very little microplastics, unlike these biodegradable waste. Compostable Plastics, meanwhile, with the & # 39 is a subset of biodegradable plastics, which are designed to degrade faster.
All five types of plastic were tested in the open air, buried in the ground and immersed in the "Ocean". Researchers measured a loss of surface area and decay over time, as well as the tensile strength, surface texture and chemical structure.
Under the open sky have finished all the bags, which are split into fragments within just nine months.
In terms of soil and water, though, it was a different story: biodegradable, oxo-biodegradable and normal plastic bags can still keep buying after three years after being buried or submerged in water.
Composting bag type made better, disappearing from the aqueous medium, within three months, and dispersed to such an extent in the soil environment and – although more fragments were found after 27 months of testing.
None of the bags are not completely deteriorated in all three environments.
Through their analysis, the researchers hope to raise awareness of the fact that "biodegradable" really means that, when it comes to plastic bags – that can be processed into industrial heat and pressure of the & # 39 object can not disappear somewhere anywhere near as fast in a natural environment,
In other words, biodegradable as the label does not mean much without the conditions and terms of the degradation are included.
The team also wants to see more stringent international standards, that is around the definition of biodegradable really means. In the UK, disposable plastic bags were collected from 5p tax since 2015 and is currently suspended from large stores in general.
The representative Vegware, which provided a compost bags, said The Guardian that "it is important to understand the distinction between terms such as compostable, biodegradable and degradable … oxo-composting the compost materials may five basic conditions – microbes, oxygen, moisture, heat, and time."
"This study raises a number of questions about what the public can expect when they see something labeled as biodegradable," says one of the research team, Richard Thompson.
"We demonstrate here that the materials tested have no consistent, reliable and relevant advantages in the context of marine debris."
The study was published in Environmental Science & Technology.