Talk by Patricia Corcoran (DSAS colloquium)

Title:

Plastic Pollution in the Great Lakes Watershed

Abstract:

The global production of plastic was estimated at 335 million tonnes in 2016. Notwithstanding the benefits of plastic, there is a lack of appropriate disposal methods as the demand for plastic grows. As of 2015, only 9% of global plastic waste had been recycled, whereas 79% had accumulated in landfills or in the natural environment. The main pathways through which plastic debris reaches marine and freshwater sinks include natural and human-made watercourses. Once in the aquatic environment, wind-driven surface currents, tides, and waves contribute to dispersal and resuspension of plastics. Our work in the Great Lakes watershed shows that the greatest abundances of plastic debris on a regional scale, and microplastics (<5 mm) in particular, are associated with high population density, plastic use and production facilities, river input, and wastewater treatment plants. Local variations in abundances are controlled by water flow, embayments and barriers, and amount of organic debris. Determining the main sources, pathways and sinks of plastic debris helps uncover the potential for ingestion and trophic transfer in various aquatic ecosystems, as well as provides a baseline on which future long-term monitoring will build.

Biography:

Dr. Patricia Corcoran is an Associate Professor and Department Chair of Earth Sciences at the University of Western Ontario. Her research focuses on natural and anthropogenic sedimentary deposits. One significant element of her research over the past decade has been the distribution, accumulation and degradation of plastic debris in marine and fresh water shoreline, river, and lake bottom sediments. Her work is supported by the provincial and federal governments, and has been featured in numerous media outlets, including National Geographic Magazine, Science Magazine, Science et Vie, the New York Times and CBC's The National.