As microplastics flood the world’s oceans, some good news out of UBC indicates the pollutants do not appear to magnify as they’re passed through the food web from zooplankton, to fish and, lastly, large marine mammals.
A researcher at the university’s Institute for the Oceans and Fisheries (IOF) sampled water with varying levels of microplastic concentrations, then combined it with data about the food webs, digestive process and dietary habits of humpback whales and killer whales off B.C.’s coast. The results showed biomagification, when substances accumulate in animals in larger concentrations as they’re passed up the food chain, scarcely occurred in the two whale species.
However the study’s author, Juan Jose Alava, principal investigator of the Ocean Pollution Research Unit, and a research associate at the IOF, cautions more data from other food webs is needed to form an accurate picture of microplastic biomagification.
“[Microplastics] are persistent because they take a long time to break down, and the material can cause some damage and health effects in marine organisms,” Alava said.
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“The takeaway is that we learned that the water and sediments are polluted with microplastics. The global ocean is basically a dump,” Alava said. “We need to change our behaviours, our preferences and our consumption. The world’s population is depending on plastics. Yet, they’re everywhere. The idea is to change to a more clean, plastic-free and biodegradable source of products.”
The model Alava built for the study will be freely available to other scientists. As more data comes in, his hope is to see a more accurate risk assessment of microplastics on marine mammals that can better inform plastic waste management decisions.
Empirical studies exist on how microplastics transfer through lower-level organisms, but this is among the first studies on complex marine food webs and top predators.
Canadians want solutions
Plastics account for about 73 per cent of marine litter, with more than 1,300 species, including 81 marine mammals, affected through entanglement and ingestion of fishing line, plastic bags and other plastics.
One study estimates that a minimum of 5.25 trillion particles weighing 268,940 tonnes is floating in the world’s oceans, coming in the form of products like microbeads in cosmetics and cleaners, or broken down from larger items like clothing, ropes, bags and bottles.
A new poll from Abacus Data commissioned by Oceana Canada found that 95 per cent of Canadians are concerned about marine plastic pollution, with two thirds supporting the expansion of Canada’s proposed ban on harmful plastics to include items like cold drink cups, cigarette filters and all forms of polystyrene, like styrofoam.
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Currently, the ban would include only six single-use plastics that Oceana says have already fallen out of favour with consumers — checkout bags, straws, sir sticks, six-pack rings, cutlery and polystyrene takeout containers.
“Canada has an opportunity to lead in the fight to end the global plastic disaster. There is public appetite for stronger federal action. Now is the time to meaningfully reduce plastic production and use, including banning more of the unnecessary and harmful single-use plastics that are choking our life-sustaining oceans,” Oceana Canada plastic campaigner Ashley Wallis said.
Oceana’s poll found 88 per cent of respondents were unaware just than nine per cent of Canada’s plastic waste is recycled.
“Recycling alone will never be the answer,” Wallis said. “Our recycling systems can’t handle the volume or complexity of materials on the market today. Meanwhile, plastic production is expected to double by 2035.”
