Daphne Bramham: A ‘smog’ of plastic may be killing our oceans
The biggest problem in the world’s oceans isn’t swirling, Texas-sized islands of discarded plastic. It’s the small stuff; the little bits you can’t see that are congregating in gyres where ocean currents converge.
If it were only big, visible chunks of floating plastic, the fix would be simple. Send some people in boats with big nets and scoops and collect it.
Unfortunately, it’s way more complicated than that and it’s why Marcus Eriksen is trying to change the narrative by using a different analogy — smog in the oceans.
Eriksen is one of the authors of the peer-reviewed study that estimated there are 244,000 tonnes of plastic in the world’s oceans. Of that, 92 per cent of the pieces are five millimetres or smaller, which works out to an estimated 5.25 trillion tiny pieces.
Some microplastics absorb toxins such as PCBs, DDT, other pesticides, flame-retardants and oil from vehicles. Others release toxins as they degrade.
As for microfibres, a study published this summer by researchers at Southampton Solent University found that as many as 2,000 fibres from fleece and polyester fabrics are released during a single washing cycle. Almost all of those find their way through municipal sewage systems to the sea.
A couple of years ago, the Great Lakes were described as being awash in microfibres with bits found enmeshed in the gastrointestinal tracts of some fish and fish-eating birds like cormorants.
And there’s growing evidence of microplastics in the Arctic Ocean. “Polar sea ice is becoming a major sink for microplastic contamination,” according to a 2014 study. “And, as the ice melts, these microplastics can be released into the environment.”
The study was cited by the Canadian government last year when it added microbeads to its list of toxic substances in 2015.
What no one knows is the extent of microplastics in the Arctic or where they come from. It’s why Eriksen, founder of The 5 Gyres Institute, and Eric Solomon, the Vancouver Aquarium’s head of Arctic programs, were sampling water during a 12-day trip through the Northwest Passage.
Because of the focus on plastics, everyone on the expedition looked for bigger plastic pieces while we were ashore on desolate, unpopulated islands. All sorts of stuff was found — shopping bags, rope, gun shell casings, plastic-coated wire and smaller, unidentifiable pieces.
But it was the micro-bits that were the real target. Eriksen and 5 Gyres “citizen scientists” dragged a 60-centimetre wide Manta trawl behind a Zodiac at about two knots for 30 minutes.
Solomon and the aquarium’s volunteers took some sediment samples as well as numerous samples from 3.5 metres below the surface.
“It’s not sexy stuff,” admitted Solomon. “It’s basically just sieving sea water.”
Several times a day, a pail full of water was poured through a metal sieve, which filtered out anything larger than 63 microns. (A micron is one one-thousandth of a millimetre.)
Both sampling methods yielded a few bits visible to the eye. One water sample viewed under a microscope had copepods (small crustaceans), translucent marine snails, phytoplankton, thin strands of fibres and a pinkish piece that looked like a granite rock.
“I’m really curious about the coloured bits,” Solomon said. “The blue pieces are the question marks for me. They have a square-ish base that comes up (under the microscope) rough, jagged with reflective flecks.”
Neither Solomon nor Eriksen was making any guesses about whether any of what they found is plastic. That requires further study.
The aquarium’s samples will be handed over to Peter Ross, head of the Ocean Pollution Research Program, to do the toxicology work. The aquarium’s lab is the only one in Canada with a $300,000 Fourier Transform Infrared Spectrometer, which will eventually not only identify plastic, but determine exactly which of 5,000 varieties of plastic it is.
But before that, the samples will be rinsed again and the bits from each sample counted and measured. Sediments will be removed using a technology Ross and his team have developed using canola oil to emulsify with the sediments, leaving the plastic floating on the top.
Other samples with phyto- or zooplanktons will be put on glass-coated polypropylene well plates, immersed in nitric acid, covered and heated until the tissues have dissolved.
Only then will the samples be put through the spectrometer where an infrared beam strikes a crystal that Ross says “excites” the electrons. Because each kind of plastic has a unique signature, the response conveyed back to the spectrometer can be identified within 20 seconds.
Why this matters is because if scientists can identify specific kinds of plastics concentrated in specific areas, they can begin to determine where they’re coming from and what can be done to stop it.
How big is the problem?
When Ross and his team sampled the water off the B.C. coast a couple of years ago, the results were astounding. One of every 34 copepods and one of every 17 euphausiids contained microplastics or fibres.
Based on their findings, they estimate that juvenile salmon in the Strait of Georgia may ingest two to seven microplastic particles each day, while returning adult salmon take in up to 91 particles.
Extrapolating from that, the researchers concluded humpback whales could scoop up more than 300,000 plastic bits daily.
Their study, published in Archives of Environmental Contamination and Toxicology last year, was described as “the first indisputable evidence that species at the bottom of the food web are mistaking plastic for food.”
Others have studied fish and bivalves sold in markets in several different countries. As Eriksen said, “If you eat oysters, you’re likely feeding on your own fleece.”
Microplastics include everything from tire dust to fibres from dryer exhaust; from broken down bits of plastic bottles, Styrofoam containers and other packaging to microbeads intentionally added to cosmetic products.
Global plastics production went from 202 million tonnes in 2002 to 299 million tonnes in 2013. By 2030, it’s forecast to reach 600 million tonnes and double that by 2050.
What is the majority of all that plastic used for? Packaging, according to the U.S. Plastics Industry Trade Association’s 2015 global trends report. That’s followed by vehicle production and medical uses.
Eriksen says the plastics come from three sources. One is unavoidable catastrophic events like Japan’s 2011 tsunami that washed 16.2 million tonnes of debris into the ocean.
Another is poor product design including the proliferation of single-use products. Some of this can be blamed on our demand for convenience. Think of single-serve coffee pods; frozen foods in ‘stand-up-straight’ plastic bags that can’t be recycled; individual cleaning wipes; and over-packaged, small items from memory cards to mascara.
Finally, there’s poor waste management. It ranges from nonexistent in developing countries to inefficient and insufficient in wealthy countries where even massive landfills and incinerators don’t seem capable of dealing with what’s thrown into them.
Even with good intentions, progress is slow. Statistics Canada reports 92 per cent of Canadians have access to recycling and 98 per cent use at least one recycling program (bottles, plastics, paper, etc.). But total residential waste disposal continues to grow.
We need to start making choices about what we buy. But we also have to decide who ought to pay the lion’s share of the fundamental switch away from being a throwaway society. Will it be producers or consumers?
Microplastics are everywhere, so there’s no time to waste. Because as we nibble away at the problem, microplastics and nanofibres are being gobbled up by almost everything along the food chain. Including us.