Lassonde professor combats microplastic contamination in Lake Ontario

Plastics are durable, lightweight and versatile, making them suitable candidates for use in a wide spectrum of products. They are essential to the daily lives of many Canadians. Despite their benefits, challenges related to the end-of-life of these materials remain to be addressed. This is especially important given the impacts of plastics on freshwater and marine systems.

Shooka Karimpour

Shooka Karimpour

Shooka Karimpour, a professor in the Department of Civil Engineering at the Lassonde School of Engineering at York University, is working to tackle the spread of plastics in aquatic systems where the decomposition of plastics is having a major impact on aquatic health.

Karimpour has received a Natural Sciences & Engineering Research Council of Canada (NSERC) Alliance Option 2 Grant, totalling $493,400 over five years to help tackle this growing problem through the project, “Hidden microplastics of the Niagara Basin: distribution, variability, and ecotoxicology in water and sediments.” Karimpour is working with Professors Raymond Kwong and Satinder Kaur Brar from York University, as well as Professors Tirupati Bolisetti and Ram Balachandar from the University of Windsor.

The team is researching the physical processes that lead to the transport and ecotoxicology of microplastics across the Niagara Basin of Lake Ontario as well as two rivers in the Greater Toronto Area. In a unique approach, the researchers are combining numerical simulations, field sampling and laboratory experiments to tackle the problem from multiple angles. Ultimately, their goal is to develop an understanding of how currents, gravity and weathering influence the transport of microplastics in aquatic environments, and how this impacts aquatic life. The research team has partnered with the Ontario Ministry of Environment, Conservation and Parks (Environmental Monitoring & Reporting Branch), Environment and Climate Change Canada (Watershed Hydrology and Ecology Research Division) and Pollution Probe to conduct this research.

Figure 1. Infographic demonstrating transport of plastics into aquatic systems. Courtesy of Professor Shooka Karimpour and her team in the Environmental Hydrodynamics Lab (EHD Lab).

Figure 1: Infographic demonstrating transport of plastics into aquatic systems (image courtesy Professor Shooka Karimpour and her team in the Environmental Hydrodynamics Lab (EHD Lab))

The transport of plastic debris by storm drains, wastewater and windage into rivers allows plastics to enter large bodies of water, such as the Great Lakes. Plastic decomposition can take centuries, and this is exacerbated in freshwater and marine systems. As a result, plastics remain in aquatic environments far beyond their urban and industrial lifespan. In freshwater and marine ecosystem, plastics are widespread and found in the deepest sea sediments and remote Arctic waters.

Microplastics are plastic pieces smaller than 5mm in size. Some microplastics are directly manufactured for use in clothing, cosmetics or household products, and others are the by-product of the breakdown of larger plastic debris. In the last decade, microplastics have been recognized as emerging pollutants due to their impact on both aquatic animals and human health.

“What we see as visible, floating plastic debris on water surface is really only the tip of the iceberg. Existing research confirms that plastics, especially microplastics, are spread across all water bodies, including Lake Ontario. Pieces of a discarded plastic bottle in Toronto, can potentially end up in sediments a hundred meters deep in the Great Lakes or travel thousands of kilometers in the water to a distant area,” said Karimpour.

Figure 2. Image depicting types and shapes of microplastics, courtesy of Professor Shooka Karimpour and her team in the EHD Lab.

Figure 2: Image depicting types and shapes of microplastics (image courtesy Professor Shooka Karimpour and her team in the EHD Lab)

In 2017, it was estimated that 10,000 tonnes of plastics enter the Great Lakes every year. The plastics in these aquatic environments not only impact the water quality but are also consumed by many forms of aquatic life and later work their way up the food chain. Estimates indicate that floating microplastics on water surfaces only account for a small portion of this pollution and the overwhelming majority of these emerging contaminants are hidden within aquatic systems in water columns and sediments. Identifying and improving the detection, distribution and environmental impact of microplastic pollution is of utmost importance.

This NSERC Alliance Option 2 grant builds on a previous SSHRC Knowledge Synthesis Grant awarded to Karimpour in 2020, for the project titled “The Fate and Transport of Microplastics in Aquatic Ecosystems: Synthesis and Directions for Future Research.” This funding is also in partnership with Kaur Brar, as well as the National Research Council of Canada. As part of this work, Karimpour presented at the SSHRC Imagining Canada’s Future Forum in April 2021.

The NSERC Alliance Option 2 grant awarded to Karimpour is a first for York University. NSERC Alliance grants fund collaborations of university researchers and partner organizations in multiple sectors. The Alliance Option 2 grants are funded up to 100 per cent by NSERC and are awarded specifically for research aiming to address a societal challenges.

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