M.Sc. THESIS DEFENCE - Anna Ryan
Anna Ryan
Department of Earth and Environmental Sciences, Dalhousie University
Title: Storm-driven Transport and Deposition of Atmospheric Microplastic in Remote Newfoundland, Canada
Abstract: Microplastic pollution is an increasing global concern due to its pervasiveness in all types of environments around the world, and the potential risk it can pose to all living organisms, including humans. In recent years, the study of how microplastic particles travel across the atmosphere has attracted increasing attention, and preliminary results have shown that rain and wind can transport and deposit large quantities of microplastics in remote regions. However, how intense meteorological events such as hurricanes can influence microplastic pollution is still unknown. In this MSc thesis, I present two studies that investigate the dynamics of atmospheric microplastic transport and deposition in Newfoundland, Canada, a relatively remote region with low population density and susceptible to intense storms. In the first study, the passage of Hurricane Larry over Newfoundland in 2021 was used as a natural laboratory to quantify storm-driven transport and deposition of microplastics. I collected atmospheric samples before, during, and after the storm to quantify microplastic deposition. I used chemical analysis of polymer types and back-trajectory modelling to determine that the majority of microplastics collected were likely sourced from the ocean. To quantify whether tropical cyclones and nor’easters can have a dominant role in microplastic pollution in the region, I collected remote lake bottom sediment samples across Newfoundland. Assuming that the lakes are fed by rain or groundwater and human impact is negligible, I hypothesized that their primary source of microplastics is the atmosphere. The results show microplastics were present in all samples and had a similar size distribution to the particles deposited during Hurricane Larry, identifying the possible link of microplastic deposition to storm events. This research provides quantitative data for the first time on how hurricanes may influence microplastic pollution in remote regions of North America. Additionally, by quantifying the level of plastic pollution in many lakes across the province, I provided a baseline dataset that can support future works aimed at investigating fresh-water environments, in Newfoundland and elsewhere, while also contributing to a comprehensive understanding of the fate and impact of atmospheric microplastics in remote environments.
Examining Committe:
Dr. Amina Stoddart,Dalhousie University - External Examiner
Dr. Vittorio Maselli, Dalhousie University -Supervisor
Dr. James Brenan, Dalhousie University - Reader
Dr. Tony Walker, Dalhousie University - Reader
Dr. Noreen Kelly, Dept. of Fisheries and Oceans - Reader
Dr. Yana Fedortchouk, Dalhousie University - Departmental Chair
Time
Location
Milligan Room, 8007 LSC, Dalhousie University