The bioplastics industry has hit back at what it describes as “misleading” headlines around a study of biodegradable and compostable plastic bags.
The University of Plymouth study, Environmental deterioration of biodegradable, oxo-biodegradable, compostable, and conventional plastic carrier bags in the sea, soil, and open-air over a 3-year period, used two oxo-degradable bags, one fossil non-biodegradable polyethylene bag, one bag marketed as – but not proven to be – biodegradable, and one product certified compostable according to the European Norm 13432, to examine the degradation of different plastic carrier bags under littering conditions.
News reports from various outlets such as The Guardian and National Geographic highlighted that “biodegradable” bags could still be used after periods of up to three years; however, European Bioplastics (EUBP) said the study confirmed that only certified biodegradable and compostable bags, designed to be taken to dedicated composting plants, had a reduced environmental impact.
“While no plastic bag should end up in the environment, period, at least it is clear that certified compostable ones will not need decades to degrade, as conventional plastic bags do,” said François de Bie, chair of EUBP.
Rowan Williams, president of the Australasian Bioplastics Association, acknowledged that the University of Plymouth had corrected its press release to clear up the confusion.
“The press release is now clarifying that the above results only concern ‘biodegradable’ bags, not certified compostable bags, which is consistent with the ABA position of biodegradable as a term being meaningless.
“Only certified compostable plastics convey the inherent property of biodegradability and the end of life for certified compostable plastics is well defined as commercial or home composting,” said Williams.
BioPak founder Richard Fine stressed that compostable packaging’s value in reducing waste to land fill must not be dismissed based on studies where material is placed in other environments than composting facilities.
“Compostable packaging is not a solution for littering, and neither is it a solution to the problem of plastic pollution. Rather, the compostable materials and packaging are designed to facilitate the collection and recycling of nutrient rich organic material such as food scraps and return the nutrients into the soil rather than allowing them to rot away in landfill,” he said.
According to Fine, compostable packaging’s simplified collection and disposal reduces leakage of plastic packaging into the environment, and as it is made from renewable resources, it also reduces consumption of fossil materials.
“Compostable packaging is just one of the ways to reduce the wide range of environmental impact caused by conventional non-compostable packaging,” he said.