NEXT MEETING: MINNEAPOLIS, MINNESOTA - JULY 31 - AUG 3 2023

E.C. Minor1, M.A. Maurer-Jones1, K.M. Schreiner1, U. Gomes1, P. Conowall1, J.M. Fox1, G.D. Schwoerer1, A. Thomas1, N. J. Poulton2
1University of Minnesota Duluth, USA
2Bigelow Laboratory for Ocean Sciences, USA

Plastics are designed to be durable, but this useful feature has led to their unintended spread though the environment. Studies of aquatic and soil systems have found plastics ranging in size from micrometers to meters. Larger plastics can lead to entanglement issues for animals and plants. Microplastics (less than 5 mm in longest dimension) have been shown to cause adverse effects when consumed by animals, with their effects appearing greater when the particles are smaller in size. The prevalence of microplastics in both field and lab settings necessitates care in sampling and analysis. Field and method blanks are needed to ensure that sample processing and analysis approaches are sufficiently clean. Appropriate control samples are required to evaluate the efficiency in microplastics enumeration, which can vary with microplastic morphology, particle size, and polymer composition. This talk addresses our adventures and misadventures in sampling Minnesota aquatic systems and dealing with the effects of complex sample matrices, such as exist in microplastics studies in fish, natural lake waters, lake sediments, and beach sands. We also describe microplastics size distributions in water samples from Lake Superior. Analyses of samples in our laboratories include microscopy and FTIR, microFTIR, flow cytometry, and pyrolysis gas chromatography mass spectrometry (pyGCMS). The pros and cons of these approaches in determining microplastic composition and size distributions will be included in our discussion of environmental samples.