Researchers from the University of Plymouth in the U.K. found that plastic bags touted as 鈥榖iodegradable鈥� and 鈥榗ompostable鈥� and capable of carrying groceries three years after being disposed of.
Research Fellow Imogen Napper and Professor Richard Thompson studied the decomposition of five plastic bag materials that are common to the U.K., in air, soil and sea environments - places that would be affected if the bags became litter.
In the open air, all the materials completely disintegrated into fragments.
In the sea and soil test environment however, the 鈥渂iodegradable, oxo-biodegradable and conventional plastic formulations remained functional as carrier bags.鈥�
These findings call into question whether 鈥渂iodegradable formulations can be relied upon to offer a sufficiently advanced rate of degradation to offer any realistic solution to the problem of plastic litter,鈥� researchers said in a press release.
In Canada, similar questions have been raised after Greenpeace that Canadians generate 3.25 million tonnes of plastic garbage each year.
Dr. Mohini Sain, professor at the University of Toronto and Director of the Centre for Biocomposites and Biomaterials Processing, told 麻豆传媒 in an email that there is 鈥渘o clear definition of biodegradability鈥� in Canada, and that if products claim to be biodegradable then they should 鈥渟pecify the time period to complete biodegradation.鈥�
鈥淏iodegradability, in general terms is an end of life option鈥ormally it should not take a long time or it should biodegrade in an environmentally responsible manner within a specified and short time period.鈥�
Sain said that in the past, companies in Canada used pure PLA (bio-based poly-lactic acid polymer) to make plastic bags that would have been biodegradable in a composting medium 鈥� but that he was unsure if the practice was ongoing.
Unlike biodegradability, Canada鈥檚 compostable certification is 鈥渨ell established,鈥� with clear definitions for products to adhere to, Sain added.
In the fight against plastic pollution, Sain says that 鈥渨e do not need all plastics to be biodegradable,鈥� as 鈥渘o bio-plastics get 100% biodegraded within a short time period鈥nd in all cases they need specific environments鈥� to fully break down.
Instead, Sain says that community efforts to compost and reuse biodegraded materials, along with public education, are essential.
