Microplastics and anthropogenic microparticles in surface waters from Yellowknife Bay, Great Slave Lake, Northwest Territories, Canada

Recent studies have identified the presence of microplastics and other anthropogenic microparticles in Arctic marine environments, but very little is known about anthropogenic microparticles in Arctic and sub-Arctic freshwater systems. Given the importance of freshwater systems to the health of northern communities, and their large input of water to the Arctic Ocean, circumpolar rivers and lakes should be considered within the context of anthropogenic microparticles in the region. Sample collections for this study were conducted in July and August of 2021 via a collaborative community-based approach. Thirty surface water samples were collected using a 300 µm Manta trawl from three sampling areas, the Yellowknife River (n = 10), Yellowknife Back Bay (n = 10), and Yellowknife Outer Bay (n = 10), to assess concentrations and transport of microplastics and other anthropogenic microparticles to Great Slave Lake, Northwest Territories. Each trawl was towed for 20-minutes, resulting in 16 to 233 m³ of water filtered per sample. Suspected anthropogenic microparticles were found in all samples, with concentrations ranging from 0.03–2.04 particles m⁻³, however, there were no significant differences in microparticle concentrations between sampling areas. A wide range of microparticle morphologies and colours were observed in the samples. A total of 1012 suspected anthropogenic microparticles were extracted from the surface water samples, of which fibres accounted for 87 % (n = 883), followed by fragments (11 %, n = 112), films (1 %, n = 7), and foams (1 %, n = 10). Our results indicate a widespread occurrence of microplastics and other anthropogenic microparticles in the surface waters surrounding Yellowknife, Northwest Territories.