The Problems With Plastics in Oceans and Waterways

2050…the year by which the World Economic Forum predicts there will be more plastic in the oceans than fish, by weight.

It’s a frightening statistic: At least eight million tonnes of plastic end up in the planet’s oceans every year. About 80 per cent of marine plastic waste comes from land-based sources, and the amount has risen exponentially in recent decades. Algalita Marine Research and Education, based in Long Beach, Cali., estimates that to clean it up volunteers would have to scour our coastlines three times a day, every day of the year. The volume of plastic refuse is so vast that the World Economic Forum has predicted that by 2050 there will be more plastic in the ocean than fish by weight. And in a recent long-term study of ocean plastic pollution (most data sets collected so far have looked at plastic ingestion by animals over the short term), scientists at Utrecht University in the Netherlands have been able to show for the first time that macroplastics, such as shopping and garbage bags and other larger items, are a scourge attributable to our times, with debris increasing in the seas in the past 60 years.  

Macro versus micro

Macroplastics, visible to the naked eye, include bottles and jerry cans; fishing gear, ropes and nets; pails and buckets and infinite other items. In the oceans they tend to be sucked into giant garbage patches buoyed by the planet’s five major ocean gyres (large ocean currents). Some of this flotsam washes up on shorelines, some stays in the gyres or sinks to the ocean floor. No matter where it ends up, it often has lethal consequences for marine life. Turtles, for instance, mistake wet wipes and plastic bags for jellyfish, eat them and die. Mammals, including whales and sea lions, get entangled and drown. Or they, too, mistake plastic for food, which blocks their digestive tracts and causes pain and starvation, as seen in several recent beached whales, where necropsies revealed stomachs full of plastic bags. Plastic waste is found as far away as the Arctic, and has even made it into creatures living in ultra-deep sea trenches, such as the Mariana Trench, more than 10,000 metres below surface. Not only are stomachs blocked as a result of our dangerous habits: cities have experienced floods due to plastic waste clogging up sewer systems. 

Sweat the small stuff

Ironically, one of the biggest dangers to our waterways is caused by the tiniest of plastic particles. Today, synthetic microfibres make up most of the plastics found in oceans, lakes and rivers. Beaches adjacent to municipal wastewater outlets are chock-full of microfibres from synthetic fabrics. Unlike cotton and wool, they’re not biodegradable and can leach chemicals as well as bind pollutants such as flame retardants and pesticides, forming toxic molecules that are ingested by plankton and other micro-organisms as well as by oysters and other shellfish. When polypropylene, a plastic often used in fleece and athletic clothing, is broken into smaller pieces, the result is more surface area onto which chemicals and persistent organic pollutants can attach, and when fish eat plankton that have consumed these particles, for instance, they ingest the pollutants. So, it’s not only the plastic per se that’s harmful, but also the chemicals contained within or that hitch a ride with them and accumulate in higher concentrations the higher up in the food chain they travel — up to humans. And once microplastics are buried in the sediment of lakes, they stick around and can wreak havoc for a very long time. According to one University of Toronto study, plastic pellets have been accumulating in Lake Ontario for some 40 years, so the long-term effect is still unknown.

Did you know?

The Great Lakes tend to be overlooked in light of ocean plastic, but they face a fate similar to that of the oceans, with a plastic concentration as high as in the seas. Some 10,000 tonnes of plastic inadvertently flow into the Great Lakes every year; 80 per cent of all the litter in these waterways is plastic, such as bottles and caps, coffee mugs and shopping bags. In Lake Ontario alone, there are 6.7 million plastic particles per square kilometre. 


Take Action

4 easy ways to help keep plastic out of our waterways

  1. Bring a reusable water bottle and mug with you; fill it at home and in coffee shops and restaurants.
  2. Say no to single-use plastic such as balloons, straws and grocery bags
  3. If you see plastic litter, pick it up and place it in a garbage or recycling bin. Litter rolls downhill or flows downstream, eventually ending up in a waterway — unless we stop it. 
  4. Join or organize a shore or riverbank cleanup. Most municipalities will hand out gloves and garbage bags for free.