Faculty of Science

Would you like some plastic with that sandcastle?

New research suggests alarming accumulations in our Great Lakes

Plastic bead borderAhhh summertime in Ontario: swimming in cool freshwater lakes and streams, fishing off the dock, hiking on endless kilometers of sandy beaches. It’s our own Canadian version of paradise, right?

girls building a sandcastle on the beachNew research suggests that plastic pellets accumulating in our rivers, Great Lakes and shorelines may be turning our pristine playground into a toxic nightmare. Surprisingly, 100 million tons of plastic debris is floating around the world’s oceans, but research into the effects of these plastics on our Great Lakes – the largest freshwater ecosystem in the world -- is relatively unchartered territory.

Enter Dr. Patricia Corcoran, Associate Professor in the Department of Earth Sciences at Western University. Dr. Corcoran and her team are conducting pioneering research into the pathways of plastic debris into the Great Lakes, specifically Lake Ontario and Lake Erie. The accumulation of plastics here has the potential for widespread impact on multiple ecosystems, food chains and even tourism.

Dr. Patricia Corcoran, Department of Earth Science

Dr. Patricia Corcoran, Department of Earth Sciences

Corcoran’s research concerning plastic debris along Lake Huron was a first for a freshwater ecosystem. Unlike the obvious plastic bottles, syringes and containers that litter our beaches, it’s the smaller, meso- and microplastics that have caught her attention, specifically plastic pellets. These lentil-sized plastics are commonly used by manufacturers, melted down and then molded into larger products.

It’s a big problem concentrated close to home. Some 47% of the companies in the plastic products industry in Canada are located in Ontario. Pellets are transported around the province, commonly spilling en route to their destinations or on factory floors where they are then swept into drains making their way through our storm sewers and eventually out to the larger bodies of water.

Just how much is getting in, and the effects they are causing, is exactly what Corcoran’s research is attempting to uncover. “The first step,” says Corcoran, “is to deduce where the hotspots are.” Her first significant find is a blob of plastic debris equal to about 25 meters of sidewalk lining the shoreline of Humber Bay. Significant amounts of plastic pellets were also uncovered along the riverbank and floating down the Humber River, a waterway that feeds directly into Lake Ontario.

Fieldwork will begin in August 2014 to identify other hotspots and to take core sediment samples from the bottoms of Lake Ontario and Lake Erie. Corcoran and her team will use these samples to identify how much plastic has already accumulated, the date it started and the rate at which it continues to accumulate. Corcoran’s team is collaborating with the Ontario Ministry of the Environment and Environment Canada on this pioneering research.

Canada geese on the beachCore samples from the lake and the pathways feeding into it have the potential to launch future research into the effects of plastic on our own lives. Current research already shows that seabirds are attracted to plastic pellets and will keep eating until their digestive tract is full, eventually starving from nutrient deprivation. Littered shorelines, both with plastics and seabird guano, are not only unattractive to tourists but are potentially detrimental to the health of children who play in the sand.

Plastic debris provides transportation for pollutants and non-native organisms to hitchhike into our freshwater ecosystem. And yet another recent study discovered plastic fibres in the stomachs of fish from Lake Erie. This is particularly significant given that approximately 65 million pounds of fish are harvested from the Great Lakes every year.

Collectively, these outcomes are posing some very serious questions for Canadians: How much plastic can these animals eat? Can the toxicity from plastic pellets be transferred to the people who eat the fish? What is the long-term impact on animal populations, tourism, natural habitats and ecosystems?

Corcoran’s pioneering research into pathways and hotspots for plastics, the rates at which they are accumulating, and the quantities that are already here, are setting the stage to answer these questions.

"Only then,” says Corcoran, “will we be able to identify what the effects truly are and understand the real impacts.”