Plastic waste posing grave threat to oceans

“I remember thinking: ‘How on earth did it get there?’” said Lindsay Porter, a marine scientist based in the Malaysian city of Kota Kinabalu, who spotted the item from a research vessel about 200 km, off China in 2009.

The teeth, gripped in their plastic gums, are part of the millions of tonnes of plastic trash that somehow ends up in oceans around the world every year. Mostly, it is more mundane stuff, the flotsam and jetsam of everyday life: picnic plates, bottles, cigarette lighters, toys, spoons, flip-flops, condoms.

Taken together, the virtually indestructible mass is now so large that it is causing environmentalists, government officials and the plastics industry itself to sit up and take note. Many scientists believe marine plastic pollution is one of the major issues — along with climate change — facing the planet.

The problem is not the plastic itself: Even those who lobby against plastic pollution acknowledge that plastic materials help combat climate change, for example by reducing the weight — and thus fuel consumption — of vehicles, or by helping to insulate buildings.
The problem is the sheer amount of the stuff out there. Low-cost, lightweight and durable, plastic erupted onto the world stage in the 1950s. Annual production of 1.5 million tonnes back then has swelled to about 250 million tonnes now, according to the trade association PlasticsEurope.

Half of the plastic produced is used only once before being discarded. Think packaging, shampoo bottles, disposable razors, yogurt cups.

Most of that ends up in landfills. Some is recycled. But a significant amount ends up in the sea, swept there via rivers or sewage drains, discarded on beaches or dumped from ships.

Exact figures are hard to come by, but some researchers estimate that 4.7 million tonnes reaches the sea each year, according to Plastic Oceans, a London-based charity that has enlisted numerous scientists to create a full-length documentary film on the topic.

Bear in mind that this stuff does not just biodegrade like food waste, wood or paper. Scientists believe it takes decades, if not centuries, for most types of plastic to degrade. That means virtually all the plastic material that has ever ended up in the ocean is still out there.

“When a plastic crate or bottle floats around in the ocean, it does not biodegrade. It only breaks into smaller and smaller pieces — which are still plastic,” said Peter Kershaw of the British marine science centre Cefas, who helps advise the United Nations on marine environmental protection issues.

Some of the debris sinks to the ocean floor. Some washes back onto land, sometimes in remote and once-pristine parts of the world. But most is gradually swept up by ocean currents, which have assembled the assorted mess into five ‘gyres,’ or garbage patches, in the Pacific, Atlantic and Indian oceans.

Threat to wildlife
Do not imagine these to be vast, tangible floating islands of trash that you can walk across. Yes, there are visible chunks of debris — some large enough to trap or choke wildlife. Mostly, however, the plastic soup consists of tiny fragments, some the size of a fingernail, some much smaller, floating on or below the surface across thousands of kilometres.

The gunk cannot be seen via satellite, making it hard for scientists to measure or track the problem. It is, however, clearly visible from up close. “It’s kind of like chunky dust, hovering in the water. You can see the change in the texture of the water,” said Lindsay.
Although these tiny fragments do not trap or choke animals the way plastic bags or abandoned nets do, they are increasingly the focus of scientific concern. Microplastics are easily swallowed and prone to absorb chemical pollutants in the sea, like pesticides, research has shown. Some scientists worry that these contaminants could end up in the food chain, the UN Environment Programme noted in a report in February, calling for intensified research.

On the upside, plastic pollution has at least started to be recognised as a serious issue.
At a conference in Hawaii in March, plastics industry associations from around the world pledged to work with governments and nongovernmental organisations to increase research and promote efforts to recycle and prevent litter. Still, recycling rates in many countries remain low. The US Environmental Protection Agency, for example, estimates that only 7 per cent of plastics were recycled in the US in 2009. In many developing nations, where plastics consumption is expected to rise sharply in coming years, awareness, and collection and recycling efforts, are still their infancy.

The focus thus has to be on preventing new debris from getting into the oceans in the first place, said Keith Christman of the American Chemistry Council in Washington.
That means more efforts by companies to minimise packaging; more efforts by the authorities to step up collection and public awareness; and more efforts by ordinary people — yes, that is you and me — to avoid throwaway plastic products and to recycle those we do use.

As for the false teeth spotted by Lindsay — they will probably continue to travel the oceans for years to come.