Microplastic pathways to Lake St. Clair as evidenced in sediment and stormwater outfall samples

Session: Microplastics in Freshwater Systems: Advances in Chemistry, Biology and Physics (3)

Ian Arturo, The University of Western Ontario, [email protected]
Patricia Corcoran, University of Western Ontario, [email protected]

Abstract

In the winter of 2019, fieldwork was conducted in and around Lake St. Clair Ontario/Michigan to determine sources and sinks of microplastics. Eight benthic sediment cores were sampled from nearshore regions and each core was split into fifteen, 1 cm slices. In the summer of 2019, five sediment samples will be collected from tributaries using a Petit Ponar, and sediment from six beaches will be sampled using a brass corer. Five direct discharge samples will be collected using a mesh net. Microplastics from benthic samples were extracted from sediment using sodium polytungstate density separation. Microplastics were visually identified using a stereomicroscope, and representatives particles will be analyzed by micro-Fourier-transform infrared spectroscopy (micro-FTIR). Plastics-related industries, major outfalls, tributaries, and watershed land use characteristics will be mapped using ArcGIS. Plastic sources and sinks will be determined using data of polymer type, plastic morphology, size, and color. This project will: 1) be the first microplastics study of benthic sediment in Lake St. Clair, 2) will provide a depositional history of microplastics in the lake, and 3) will fill important knowledge gaps related to microplastics in the Laurentian Great Lakes System.