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An Assessment Of The Spatial And Temporal Distribution Of Microplastics In Surface And Subsurface Sediment Of Lake Huron, North America, Sara L. Belontz

Electronic Thesis and Dissertation Repository

The awareness of and the data on the prevalence of microplastic (plastic particles <5mm) pollution in freshwater environments is rapidly increasing, as low-degrading polymers are being detected in various environmental matrices of the Laurentian Great Lakes. However, the accumulation, distribution and deposition of microplastics in offshore depositional environments of the Great Lakes, and particularly Lake Huron, is relatively unknown. In this study, benthic sediment from various Lake Huron waterbodies (main basin, Georgian Bay, the North Channel, and Saginaw Bay) was quantified for microplastic particles (fibres, fragments, films, and beads). The North Channel contained the greatest microplastic abundances, averaging 47,398 particles per kg^-1 dry weight sediment (p kg^-1 dw), followed by Georgian Bay (21,390 p kg^-1 dw), the main basin (15,910 p kg^-1 dw) and Saginaw Bay (1,592 p kg^-1 dw). The results suggest that microplastic abundances in offshore settings are positively correlated with increasing water depth (p=0.004) and are controlled by lake bottom geomorphology. Hydrodynamic processes are a prevailing force driving microplastic dispersion and deposition into the offshore, in contrast to source-based drivers closer to the shoreline. Sediment cores were examined from …