Factors controlling the abundance, distribution, and composition of macroplastic and microplastic particles in tributary, beach, and benthic sediments of Lake Erie, Ontario

Plastic pollution in the Laurentian Great Lakes is becoming a significant environmental concern with the threats of species entanglement, adsorption of toxins such as endocrine-disrupting chemicals (EDCs) and persistent organic molecules (POPs), and subsequent ingestion. Lake Erie tributary (by Petite Ponar), beach (by Split Spoon sampler), and benthic sediments (by Shipek grabs) were collected and evaluated for microplastic particles (0.5 mm) (by quadrats and transects). These results were mapped using ArcGIS software to show distribution and abundance in regards to quaternary watershed population density and plastic industrial plants, manufacturers, and distributors. Tributaries in urban areas were more abundant in microplastics than in more rural tributaries. At beaches, backshores were more abundant in microplastics than in the foreshore, likely due to natural beach dynamics of sediment accumulation. The greatest abundance of microplastics was found in the Western Basin of Lake Erie, where the Detroit River drains into the lake. Quaternary watersheds borderingLake Eriewith higher population densities were most abundant in microplastic and macroplastic pollution. Macroplastics were most abundant at beaches in highly populated areas, and macroplastics were least abundant at beaches that were part of conservation areas. A random selection of microplastic fragments and microbeads were analysed using Nicolet Almega Dispersive Raman Spectroscopy and NXR FT-Raman Spectroscopy to determine types of plastics. Polyethylene was the most common microplastic observed among this sample selection. Overall, high population density around the sampling locations correlated to a higher abundance in plastic debris. Conservation areas had the lowest abundance of plastic debris; therefore, employing conservation area environmental practices could be beneficial to reducing plastic debris at other locations along Lake Erie