It turns out those "biodegradable" plastic shopping bags can not be good for the environment as at first glance.
The first of its kind study published in the journal Environmental Science & Technology, found biodegradable bags were still able to carry the purchase after immersion in water and soil for three years.
For the study, researchers conducted tests for three consecutive years on five different types of bags, currently offered by popular supermarkets – biodegradable, oxo-biodegradable, compostable and high density polyethylene.
"These materials were exhibited in three natural environments; under the open sky, it is buried in the soil, and is immersed in sea water, as well as in controlled laboratory conditions, "the report explained.
The bags were checked at regular intervals, with the level controlled wear.
Each of the bags broke up into fragments upon contact with the air for nine months, but three of the materials – including biodegradable bags – still intact after more than three years, buried in the soil or left in the sea.
In fact, bags are not only remained intact, but can still carry almost 2 kg of food.
Compostable bags are friendly to the environment when out at sea, breaking down into large pieces after three months in the marine environment.
However, they still can be found in the soil after 27 months – even though he was unable to carry out any products.
Researchers doubt, some of these products should be sold, together with statements claiming that they can be "recycled back into nature" or "plant-based plastic alternative."
The study also highlights how the term "biodegradable" may confuse consumers who think the bag will disappear if dropped. However, the researchers argue that it is not an argument against the development of biodegradable waste or compostables.
"Taken together, our results showed that none of the bags can hope to show a significant deterioration over a period of three years, in all environments," the report said.
"Therefore, it is not clear that the oxo-biodegradable or biodegradable formulations provide a sufficiently higher rate of deterioration to be beneficial in the context of reducing marine debris, as compared with conventional bags"
The study comes after Woolworths, Coles and other retailers have banned single-use plastic bags in July last year.
National Retail Association (NRA) is estimated at 1.5 billion disposable plastic bags for carrying were eliminated in the first three months of self-imposed ban.
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