February 18, 2013
Almost half of the world’s marine animals and a fifth of its seabirds are at risk of becoming entangled or eating the stuff, prompting ecologists to call for the worst plastics to be declared hazardous materials.
Without action, the international group estimates, the planet could have another 33 billion tonnes of plastic by 2050. That would fill 2.75 billion garbage trucks, enough to wrap around the planet 800 times if lined up end to end, the researchers say in a commentaryin the current issue of the journal Nature.
“This could be reduced to just four billion tonnes if the most problematic plastics are classified as hazardous immediately and replaced with safer, reusable materials in the next decade,” they say.
Industry officials were quick to call the idea “neither justified nor helpful” saying plastic debris is better tackled through more research and “public-private partnerships.”
The ecologists say the physical dangers of plastic debris are “well enough established” and the chemical dangers “sufficiently worrying” to warrant regulatory action now.
Less than half of the 280 million tonnes of plastic produced around the world annually ends up in a landfill or being recycled. Much of it becomes debris that can threaten both humans and wildlife, ecologists Chelsea Rochman, at the University of California, and Mark Anthony Browne, at the U.S. National Centre for Ecological Analysis and Synthesis write in the commentary, which was also signed by eight colleagues from Japan, Europe and the U.S.
They note that the United Nations-sponsored Convention on Biological Diversity reported last year that all sea turtle species, 45 per cent of marine mammal species and 21 per cent of seabird species can be harmed by eating or becoming entangled in plastic.
Larger pieces, such as floating bottles, pontoons and bags, can carry species to new habitats where they can kill or injure ecologically and commercially important species, including mussels, salt-marsh grasses and corals.
And as plastic degrades into smaller pieces, studies have not only shown it gets into creatures’ stomachs but also suggested that bits of “microplastic”, and some of their chemical components, can get into cells and tissues.
Another problem is that plastic debris can act like a magnet for other pollutants. “Pesticides and organic pollutants such as polychlorinated biphenyls are consistently found on plastic waste at harmful concentrations 100 times those found in sediments and one million times those occurring in sea water,” the report says.
“We believe that manufacturers of plastic, along with the food and textile industries that rely heavily on it, should have to prove that their products and packaging are safe,’’ the researchers says.
They say the focus should be on the four most problematic plastic first – PVC, polystyrene, polyurethane and polycarbonate that make up roughly 30 per cent of global production. They are difficult to recycle and are made of “potentially toxic materials.” PVC is used in construction, such as in pipes that carry drinking water; polystyrene is used for food packaging; polyurethane in furniture; and polycarbonate in electronics.
Ultimately the researchers say they would like to see regulation force development of a “closed-loop system” in which all plastics are reused and recycled.
“Recycling often involves burning plastics and using the energy released for other purposes, but incineration can generate priority pollutants and greenhouse gases,” the report says. “In a closed-loop system, plastics would be continually reused and replenished only when materials become too degraded.”
The Canadian Plastics Industry Association, which represents the country’s $17.6-billion industry making everything from blue recycling boxes to plastic bags, did not respond to requests for comment.
Steve Russell, vice-president of plastic at the American Chemistry Council in Washington, says the makers of plastic “agree that litter doesn’t belong in our oceans, waterways or any part of our natural environment.” But he said in a statement “the suggestions by the commenters in the journal Nature are neither justified nor helpful.”
“The plastic products we use every day — from milk jugs, to food packaging and medical devices — are composed of stable, long-chain polymers, “ Russell said. “Plastics used in food contact and medical device applications are evaluated for safety by governments around the world. And the plastics identified by the authors as ‘higher priorities’ are used in durable applications (pipes, siding, roofing, refrigerators), which are not generally littered or found in the ocean.”
Russell said “Scientists have long understood that persistent organic pollutants (POPs) can bind to organic compounds, such as plastics; what is currently not known is whether pollutants bound to plastics are then bioavailable, or a significant route for exposure to marine life.”
“Plastics makers agree more research is needed,” he said, adding the industry is supporting international studies, private-public partnerships and projects to prevent marine litter.
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