01.01.2022

Biodegradable Shopping Bags Buried For Three Years Still Work

A new study casts doubt on the viability of biodegradable plastics as an answer to plastic pollution. in 2015, Richard Thompson, a British marine biologisthe and his graduate students at Plymouth University buried a collection of bags labeled as biodegradable in the school’s garden. Three years later, when the bags were dug up, they not only had remained intact, they still could carry almost five pounds of groceries. The indestructible qualities of biodegradable bags are just one of the findings in a first-of-its-kind study published today in the journal Environmental Science & Technology. ​The research documents deterioration of five types of shopping bags that were immersed in water, buried in soil, or exposed to outdoor air as if litter. Thompson and his team tested bags commonly dispensed in retail shops around Plymouth and concluded that none of them–including compostable bags­–reliably deteriorated enough over three years to give them any environmental advantages over conventional bags. The study highlights how the term “biodegradable” can confuse consumers, lulling them into thinking the bag will simply disappear if thrown away. If consumers think they are being even more responsible by adding biodegradable bags to their recycling bins, that can destroy efforts to collect conventional plastic bags for remanufacture into new bags, the scientists warn. Chemical additives in biodegradable bags can contaminate the mixture, rendering it unusable. “There is no magical degradable material that will breakdown in a very short time in all environments that you expose it to. That does not exist,”. Both the United Nations and the European Union have staked out positions against biodegradables. The UN, in a report published in 2016, flatly declared that biodegradable plastics are not the answer to marine plastic pollution. Credit: WASTE ED