Claims that biodegradable and compostable bags are not fit for purpose because they do not degrade in the natural environment are flawed, according to trade association European Bioplastics (EUBP).
It was responding to a report carried out by Plymouth University that found biodegradable and compostable bags did not degrade properly – and even after three years could still be used to carry groceries.
EUBP said the bags were designed to degrade in an industrial process and not within the natural environment, nor were they designed to reduce littering. It said the report is “misleading” the public.
Managing director Hasso von Pogrell said: “Plastic products certified to be industrially compostable are no solution for littering. Testing them as if they should be is misleading the public’s perception of the technology.
“It creates the impression of the product lacking in performance, even though the performance in the intended environment has not been tested at all.”
EUBP argued that the report actually showed the importance of using correct labelling and certification.
Chair François de Bie said: “The study confirms that only certified biodegradable and compostable bags – designed to be collected with bio-waste and organically recycled in dedicated composting plants – even if mistakenly littered in the environment due to bad habits, have a reduced environmental impact.”
He argued that while no plastic bag should end up in the environment, “at least it is clear” that certified compostable ones will not need decades to degrade, unlike conventional plastics.
Five bags were tested in the Plymouth study: one fossil non-biodegradable polyethylene bag, two oxo-degradable bags, one bag marketed as biodegradable and one bag certified compostable according to the European Norm 13432.
EUBP argued that oxo-degradable products have already been banned by the European Commission. It added that the carrier labelled as biodegradable was said to be in accordance with standard ISO 14855, which is not a standard on biodegradation but specifies an optimum aerobic biodegradability of plastics.
It argued that the biodegradability of plastics has been “clearly defined and linked” to the standard EN 13432 for industrial composting, and not for home composting or breakdown in the environment.