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In the context of the widespread occurrence of microplastics (MP) in the Canadian environment, our project aims to support the adoption of effective MP mitigation policies based on understanding sources, pathways, and evaluating selected control strategies. We have 4 approaches. (1) We are developing new analytical tools to enable MP identification and classification, including developing high affinity MP ligands to allow for sensitive and specific MP identification in complex media (Awada et al. 2022). (2) We are investigating air, water and soil transport pathways, total loadings and source contributions across remote (Dorset), agricultural (Thames River), and urban (Etobicoke Creek) watersheds in Ontario. A necessary prerequisite is developing replicable, repeatable and representative harmonized sampling and sample preparation methods. Here, we are evaluating four air sampling methods, comparing and testing water sampling methods, and developing optimized sample preparation methods involving digestion procedures. (3) We are testing mitigation measures, namely Litta Traps and bioretention cells, both of which are intended to capture MPs in stormwater and that are proving to be useful methods. (4) We are developing a knowledge network that includes private and public sector stakeholders that could implement innovations and/or best practices arising from the study. [ABSTRACT FROM AUTHOR]

Urban streams and rivers are important pathways for microplastics (MPs) and other anthropogenic particles (e.g., plastic pellets, foams, tire wear) entering the Great Lakes. Well-tested, robust, and replicable sampling and digestion methods are needed to obtain representative and comparable data for use in loadings analysis, benchmarking, source tracking, etc. We conducted a systematic investigation of typical stream sampling procedures to assess sampling efficiency, and digestion extractions to minimize MP degradation while maximizing removal of abundant, complex organic matter (OM) using spiked MPs. We found that bulk water sampling using pumps and bucket grabs provided accurate estimates of MP (63-1000 µm), while net sampling (250 pm screen mesh) had lower recoveries for various shapes and sizes of MPs (20-50% for fibers; 70% for foams, both >300 µm). Results showed that sample digestions using a combination of the oxidative-alkaline solutions were more effective for eliminating OM (88-95% mass reduction) than Fenton's digestion alone (77%). The presence of OM mitigated the impacts of digestion solutions on susceptible particles. Thus, quality control spikes should include OM to mimic sample matrices. These protocols balanced efficiency (time and effort) and effectiveness (maximize removal of OM) for complex urban water. [ABSTRACT FROM AUTHOR]

Microplastics and anthropogenically sourced microparticles (MP-APs), such as synthetic, semi- synthetic and processed natural fibres, are of rising concern globally due to their inherent durability and persistence in the environment. Moreover, they are of high concern due to ingestion and inhalation exposure, and the chemicals associated with their presence. The abundance and distribution of MP-APs in marine environments has been studied extensively. Comparatively, atmospheric transport pathways are understudied. Representative air sampling and quality assurance and quality control (QA/QC) methods are needed to assemble comparable, representative data, especially where collection occurs in remote locations that favour the use of passive sampling methods. We developed QA/QC methods that included blanks and standardized reference materials representative of atmospheric particles based on their morphology. Over one year, diverse collection methods used in atmospheric-related sampling were used in this comprehensive study to compare the efficiency of MP-AP collection in ambient air (for particles 10 µm - 5 mm) and analyzed using Laser Direct Infrared and Fourier Transform Infrared. These sampling methods included two types of bulk deposition samplers; Nipher gauge and a bottle and funnel, a wet precipitation-only sampler, several types of passive samplers; moss bags, polyurethane foam disks, and adhesive strips, and finally, complemented by active high-volume air sampling. Results will be presented. [ABSTRACT FROM AUTHOR]