By John Lloyd, Benalla Sustainable Future Group
Next time you accept a degradable plastic bag at a store, think again – you may be doing little to help the environment and adding dangerous microplastics to rivers and oceans, experts say. This warning has prompted a Senate committee to call for a public awareness campaign to explain the differences between degradable, biodegradable, compostable and traditional plastic bags – and how they should be disposed of. (Education needed on degradable plastic bags, The Age, 26/4/2016)
“Degradable” plastics, commonly used for shopping and rubbish bags, contain additives that make them disintegrate more quickly than traditional plastics. Some people refer to these products as “biodegradable”. While such bags do not remain for decades in the environment as large debris, they can break into smaller and smaller particles until they become microplastics – tiny fragments less than five millimetres in size.
When microplastics enter the marine environment they can choke seabirds, poison wildlife and accumulate up the food chain, turning up in seafood eaten by humans.
The Senate committee has produced a report into the “toxic tide” of marine plastic pollution which includes plastic shopping bags. Tony Underwood, emeritus professor of experimental ecology from the University of Sydney, told the enquiry that biodegradable plastic may become less obvious to the naked eye over time but it simply turns into smaller forms of plastic more quickly. He said, “It is not a solution to anything much, unless we are quite happy to shift it all into particle sized plastics rather than plastic bag-sized plastic.”
Kathy Townsend, from the University of Queensland, told the Senate committee that consumers were largely confused about different types of bags and using the terms “degradable” and “biodegradable” plastic inspired more littering because people wrongly believed it would “degrade and go away”. She also said that the rapid disintegration of such plastic makes it “available to animals much faster than it would be otherwise”.
It seems that degradable and biodegradable plastic bags are in the end no better than traditional plastic bags and in fact could be more harmful to the environment because of the speed at which they break down. So don’t be fooled by the label.