Microplastics (MPs) are increasingly concerning from both public and environmental health perspectives. Our team represents a multi-disciplinary network of researchers from several institutions and organizations, including the ocean conservation organization Ocean Wise, three UBC faculties, the Woods Hole Oceanographic Institute, Environmental Monitoring and Management Division at Metro Vancouver and Environmental Engineering Services at the City of Vancouver. Collectively, we are uniquely positioned to significantly contribute to inform science-based solutions to plastics in the Canadian environment.This proposal aims to substantially advance technologies to accurately quantify and characterize MPs pollution, including microfibers, in aquatic environments. As land-based activities play a key role in introducing MPs to the ocean, coastal urban watersheds are ideal to apply these technologies and study entry pathways of MPs. The Strait of Georgia is heavily urbanized and sources of contaminants (i.e. stormwater/runoff, atmospheric deposition, combined sewer overflows, rivers and wastewater outfalls) can be well constrained. Our goal is to deliver a comprehensive, solution-oriented research package that combines a) the development of a suite of innovative technologies for the accurate quantification and characterization of MPs in marine waters, plankton and planktivorous fish; b) studies on the sources, transport and fate of MPs in the Strait of Georgia (SoG) and its urbanized watershed; c) experiments on microbial-mediated MPs degradation; d) pioneering predictive models to evaluate the ultimate fate of MPs in SoG. We aim to identify the processes controlling MP dispersal, biological uptake, degradation, sedimentation in SoG, and export to the Pacific Ocean. Our findings will have direct implications for urban management of drainage water and liquid wastewater practices; for the private sector as firms seek to design and manufacture more sustainable materials; and for the consumer and homeowners; and regulators and policymakers working on plastics, material design and trade at the local, national, and international level.