Supermarket plastic bags do not help protect our precious sea life

January 24th, 2013 by Richard Lord

Five pence may not seen like much money to pay for the convenience of a thin-film plastic shopping bag but in a resource constrained world avoiding this superfluous purchase has many benefits.

Plastic bags thrown out with one bag of household waste in St Peter Port on 23 January 2013 (click image to expand - ©RLLord)

Supermarket plastic bags that are purchased are usually used for a very short time, and although they can be reused, most end up in the waste stream, where they go to landfill to decay over many decades; or worse, they blow around the countryside.

Some of them end up in the sea where they have killed and injured marine birds, turtles and cetaceans.

There’s an irony to the very noticeable bright green ‘forever fish’ plastic supermarket bag that is entering Guernsey’s household waste stream.

The print on the bright green plastic bag states that all the profit from purchasing the bag will go towards protecting and saving “our precious sea life, oceans and beaches”, but the very act of purchasing this bag has the potential to be injurious to marine life.

Besides the death and injury plastic bags cause to marine life through entanglement and intestinal blockage, plastic microfibres also have the potential to cause harm.

Plastic degrades slowly.  Many plastic items will outlasts our lives, but as plastic degrades it breaks down into smaller and smaller fibres and becomes microplastic.

In the ocean, these plastic fibres attract hydrophobic toxins such as polychlorinated biphenyls and dioxins.

These toxin-coated microfibres are entering the marine life food chain with unknown consequences.

Scientists at Plymouth University and the UK Marine Biological Association have found that over a third of the fish that they sampled from an area ten miles off Plymouth in the English Channel contained microplastic fibres.

Their study is published in the paper ‘Occurrence of microplastics in the gastrointestinal tract of pelagic and demersal fish from the English Channel‘ in the journal Marine Pollution Bulletin.

Forever fish supermarket plastic bag on Pedvin Street, St Peter Port (click image to expand - ©RLLord)

Professor Richard Thompson, one of the authors, said that plastic debris in the world’s oceans comes from a number of sources, including personal care products, such as facial scrubs and exfoliators, which use microplastics as abrasives, and also from the decay of plastic bags and bottles.

Professor Thompson said “‘we don’t need to have plastic debris in the sea. These materials are inherently very recyclable, but regrettably they’ve been at the heart of our throw-away culture for the last few decades.”

“We need help from industry and manufacturers to widen the potential for every day products to be reusable and recyclable,” he said.

Our world is accumulating plastic. Although plastic is useful in many products, in the long run disposable plastic bags do more harm than good, and reducing their use by reusing bags reduces this risk.


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