Abstract:

Anthropogenic particles (AP) are ubiquitous in the environment. Recent research has shown that the atmosphere may be a significant source and transport mechanism of AP into aquatic environments through wet and dry deposition. Source to sink dynamics of AP in the environment is important to consider for the development of risk assessments considering AP exposure. This study aims to determine the relative contributions of known urban sources of AP into the atmosphere, what factors may increase AP deposition, and to determine transport potential into Etobicoke Creek, an urban watershed. Samples were collected passively and actively at four sites in Toronto Ontario including the University of Toronto St. George Campus (UofT), the Ministry of Environment Conservation and Parks (MoE), High Park, Pearson Airport, and The Centre for Atmospheric Research Experiments (CARE). Passive sampling was done over a period of two weeks using a bottle and funnel to collect bulk (wet and dry) deposition, as well as a copper-based adhesive microscope slide left in a sampling house. Active sampling consisted of using a total suspended particulate (TSP) sampler to capture total suspended particulate matter in ambient air over 24 hours. Particles greater than 106µm were counted and characterized using an Olympus SZ61 stereo microscope, and particles less than 106µm were identified using µ-Fourier Transform Infrared Spectroscopy (µ-FTIR). The particles that have been identified and characterized so far are from UofT and CARE. Pre-liminary results show that during the winter, there is a greater abundance of particles at UofT (2462.85 particles/m2), a heavily urbanized site, compared to CARE (1963.91 particles/m2), a rural site. Fibres were determined to be the dominant AP morphology in bottle and funnel samples at both UofT and CARE. Finally, a positive correlation between average precipitation and particle abundance was found within bottle and funnel samples collected at UofT.