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oa A Preliminary View of Sinking and Suspended Microplastics in Earth’s Largest Freshwater Lake by Area
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IMOG 2025, Sep 2025, Volume 2025, p.1 - 2
Abstract
Microplastic particle abundances in the surface waters of Lake Superior, earth’s largest freshwater lake by area, are similar to average values in the North Atlantic Ocean. Recent research employing in situ pumping shows that microplastic particles exist not only at the surface but throughout the lake water column. To investigate whether polymer density affects a microplastic’s fate in the water column, this study compared microplastics characteristics in sinking particles from sediment trap samples and suspended particles collected by in situ pump. Sinking and suspended microplastics from the open lake looked similar in terms of polymer composition and size distribution. Polypropylene and polyethylene, both of which are less dense than freshwater, comprised roughly half the sinking particles and two-thirds of the suspended particles. The sinking particles did have a more diverse collection of denser polymers, including polyurethane and polycarbonate, and a higher proportion of polyamide than was present in the suspended particles. The average length of sinking and suspended microplastics was the same. The density of the polymer and particle size, therefore, do not appear to be good predictors for inclusion in sinking vs suspended particles.
