Sources and fate of plastic-associated contaminants in the environment- novel analysis strategies to evaluate human and environmental exposure

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Plastics are a global pollution problem. Their global annual production is estimated at around 245 million tons. A major side effect of this immense production and use of plastic products is an increasing pollution of the environment with plastic-associated contaminants, including microplastics and hazardous chemical plastic additives. Microplastic and many chemical plastic additives are a challenge for current environmental and human health risk assessment, because they often do not meet the standard risk assessment criteria of persistence, bioaccumulation potential and toxicity. This makes it difficult to risk assess and regulate them, even though there are strong scientific indications for environmental and human health impacts for many of these plastic-associated contaminants. To evaluate potential risks from plastic-associated contaminants, established methods for chemical risk assessment need to be adapted to account for the specific environmental transport and fate of microplastics and emerging plastic additives. The aim of my long-term research program is to facilitate this process by developing methods to understand the underlying mechanisms for plastic-associated contaminant occurrence and transport in the environment. Within the five years of the Discovery Grant research, I will identify plastic-associated contaminants with a high risk for human exposure from a product life-cycle point of view, with a focus on potential contamination of freshwater and drinking water resources in Toronto. The short-term objectives for this research proposal are to - Identify priority plastic-associated contaminants in urban water which are highly linked to human exposure, - Analyse microplastics as co-contaminants or sources for persistent and mobile organic contaminants (PMOCs), - Determine how contaminant profiles and potential emissions of plastic-associated contaminants into water and food change over the "life-cycle" of a plastic product. These short-term objectives will be achieved through a combination of state-of-the-art chemical analysis, multivariate statistical analysis of factors that impact the potential for human and environmental exposure, and experimental investigation of PMOC mobility into groundwater. The outlined research will create new knowledge on the PMOC physical-chemical properties and plastic product properties that impact plastic-associated contaminant patterns and concentrations in consumer products and drinking water in Canada. The generated knowledge will advance the field of plastic contaminant research and facilitate impactful chemical management and policy development. The HQP trained through the program will have the skills to be leaders and innovators for state-of-the-art instrumental chemical analyses and mechanistic understanding of chemical transport in the environment.