Hidden microplastics of the Niagara Basin: distribution, variability, and ecotoxicology in water and sediments

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Plastic debris is found globally from mountain tops to seafloors and is a result of improper end-of-life management of plastic waste. Once the plastic debris reaches a body of water, water acts as a transport vehicle and distributes and spreads the particles. Due to their slow degradation processes, plastics can last in aquatic environments for centuries if not for millennia, and hence have long-term adverse economic and ecological impacts. Microplastics (MPs) are plastic particles smaller than 5mm and are found even in deep sea floors and sediment samples from remote arctic areas. Due to their size, MPs can be ingested by various aquatic animals, ranging from tiny creatures like zooplankton to sharks and whales and move up into the food chain. In the Great Lakes, it is estimated that combating and minimizing plastic pollution will cost $400 million annually. Different clean-up technologies have emerged in the past decade, such as aiming to collect floating large plastic debris from ocean and lake surfaces. Several recent studies, however, suggest that the surface plastic accumulation only accounts for about 1% of global aquatic plastic pollution. The remaining 99% of aquatic plastics are "hidden" in the water column and sediments. Lake Ontario is located in the vicinity of densely populated, industrial, and touristic regions. The water quality has been severely affected by human activities. Field-based studies have shown disproportionally high concertations of MPs in water column and sediments in Lake Ontario. Despite their importance, our knowledge of the distribution of aquatic MPs is limited. Our interdisciplinary research will investigate the physical processes responsible for the transport accumulation, and ecotoxicology of MPs in the western basin of Lake Ontario, known as the Niagara Basin. Using combined modelling and direct water and sediment sampling efforts, we aim to understand the impact of currents and gravity flows in the transport of MPs and formulate some of the important weathering processes in Lake Ontario. Furthermore, we will investigate MP influx variability and assess the resultant ecological implications of MP variability on native and invasive organisms. In partnership with Environment and Climate Change Canada, the Ontario Ministry of Environment, Conservation, and Parks, and Pollution Probe, this multi-disciplinary research will bring together researchers with expertise in fluid mechanics, environmental science, watershed hydrology, and toxicology. These federal and provincial partners will benefit from the generation of new research knowledge to improve their practices and policies in the management and risk assessment of MPs in Lake Ontario.