Research at University of Waterloo has quantified sources and flows of microplastics in Canada that are released to the environment. The 2023 masters thesis by Cassandra Sherlock examined tire wear, paint degradation, clothes washing and other sources of microplastic generation (particles smaller than 5 mm). The method of materials flow analysis was used to track flows from source to release and estimate loads into different environmental compartments. Tire wear accounts for the majority of the load. The total amount works out to about 1.5 kg of microplastic release per person per year.
However, microplastics releases to the Canadian environment are tiny compared to industrial pollution. Our total estimate of 60,000 tonnes (including 30,000 tonnes released directly into the environment) puts microplastics in the same order of magnitude as many known harmful pollutants released to the Canadian environment. The microplastic release equates to about 2% of the mass of the total amount of hazardous pollutants directly released by Canadian industry into the environment.
Government of Canada recorded 2.92 million tonnes of pollutants released directly to the environment in 2022 covering 320 substances across 7000 point-source industrial facilities (NPRI 2023). This included 236,000 t of Volatile Organic Compounds (VOC) released to air, 48,281 t of ammonia released to water, and 15,000 t of ethylene glycol released to land. However, these accounts are conservative as they do not include dispersed sources like vehicles, small businesses, construction sites and households – which would add considerably to some categories.
A 2024 estimate of macroplastic emissions (particles greater than 5 mm) provides parallel estimates of plastic pollution. Cottom et al. (2024) estimated global macroplastic waste emissions at 52 Mt, split 60:40 between burned waste and unburned debris. This works out to an average of about 10 kg per person per year globally. But the number is divided very unequally around the world. It is much lower for high income countries like Canada, and much higher for low-income nations without functioning waste management systems, nations like Thailand, Nigeria and Pakistan. Canadian emissions are about 0.06 kg of macroplastic; whereas a nation like Somalia releases about 14 kg of microplastic per year (Cottom et al. 2024).
For further context consider that Canada’s greenhouse gas (GHG) emissions in 2021 were 670 Mt CO2 eq, which on a mass basis would be 10,000 times greater than microplastics releases.
References
Canada (2024). National Pollutant Release Inventory. Government of Canada. Accessed August 2024 at https://www.canada.ca/en/services/environment/pollution-waste-management/national-pollutant-release-inventory.html
Cottom, J. W., Cook, E., & Velis, C. A. (2024). A local-to-global emissions inventory of macroplastic pollution. Nature, 633(8028), 101–108. https://doi.org/10.1038/s41586-024-07758-6
Sherlock, C. (2023). A Big Tiny Problem: Flows of Primary Microplastics in Canada. http://hdl.handle.net/10012/19809
