Philippe Van Cappellen, Canada Excellence Research Chair in Ecohydrology at the University of Waterloo, is leading a team studying the accumulation and consequences of plastics in the Great Lakes. His research involves identifying which types of plastic are found, and where high concentrations of plastics are, which could lead to prevention strategies.
Talking to The Waterloo Region Record, Van Cappellen explains how plastic debris in the Great Lakes—and in the world’s oceans—might be a significantly more serious environmental problem than previously realized.
“[Plastic] is often the forgotten contaminant of our aquatic environment,” said Van Cappellen. Since it is so durable, it doesn't degrade in seas and lakes: it simply breaks down into smaller and smaller particles that can be easily gobbled up by birds, fish and other aquatic animals such as shellfish, he added.
Scientists are particularly concerned about microplastics, tiny fragments and fibres of plastic that are being found even within the muscle tissue of fish and other wildlife.
Even more concerning is that plastic has been found to act like a sponge, concentrating toxic chemicals. These toxins include heavy metals and chemicals that have since been banned, including DDT and PCBs, which have severe environmental effects and are known to cause cancer and birth defects. These toxins are ingested in the food web by animals, which can spread the contaminants to humans.
Van Cappellen said research on plastics in the Great Lakes is relatively new, and scientists have more questions than answers: "How much of it is there? In what form? Where is it accumulating? How widespread is it? What are the consequences for organisms?"
Preliminary research has found plastic everywhere in the Great Lakes, with the highest densities in Lake Erie. Researchers have found everything from toys to food wrappers, water bottles and cigarette butts (which are made from plastic fibre and are the most common form of plastic litter worldwide).
"We've also been finding lots of plastic pellets," said Alex Driedger, a master's student working with Van Cappellen. The tiny, seed-sized pellets are the raw material of the plastic industry, which melts them and moulds them into useful products. Microplastics like these move much more easily from one habitat to another, are most easily ingested by wildlife, and are the hardest to clean up.
Once we know what kind of plastics are out there, "you can start saying something about the sources of the pollution," and you can start figuring out how to prevent or limit that pollution, Van Cappellen said.
His team is using readily available satellite information to see if it can help identify where plastic is accumulating most in the Great Lakes.
Sharp changes in surface water temperatures and the amount of chlorophyll can indicate where currents converge in the Great Lakes, Van Cappellen said. "The working assumption is that where the currents converge is where the plastics are."
Where the currents converge is often where aquatic life converges, he added, "so, that's where we should focus our attention. [For me], this is the tip of the iceberg."