Microplastics in the Water-column and Sediments of Western Lake Superior as Determined via Microscopy, Pyr-GC/MS, and FTIR.
While the presence of plastic pollution is well known in the world’s oceans and is beginning to be documented in the world’s freshwater systems, there is not yet understanding of the distributions, chemical compositions, fates and ecological impacts of plastic particles in most aquatic systems. Microplastic particles (≤ 5.0 mm) are of particular concern due to their direct biological effects (such as false satiation), their roles as sorbents of other chemical compounds, and as vectors for invasive species. In this study we evaluate the magnitude, distribution, and common polymers of microplastic pollution in surface waters and sediments in western Lake Superior, the deepest and most pristine of the Laurentian Great Lakes. Techniques used to quantify and/or identify microplastic particles include microscopy, Pyrolysis-Gas Chromotagraphy/Mass spectrometry (Pyr-GC/MS), and Fourier Transform Infrared spectroscopy (FTIR). Despite the low human population density in Lake Superior’s watershed, microplastic fibers, fragments, and beads were identified. Results of this study include the identification of microplastic polymers common to western Lake Superior’s surface waters and sediments as well as magnitudes of microplastic concentrations/abundances among sample sites.
Erik Hendrickson, Elizabeth Minor, and Kathryn Schreiner