From Rivers to Lake: Microplastics in the Water Column and Sediment in Milwaukee, WI

Session: Microplastics in Freshwater Systems: Advances in Chemistry, Biology and Physics (2)

Sherri Mason, Penn State Behrend, [email protected]
Peter Lenaker, U.S. Geological Survey, [email protected]
Steven Corsi, USGS, [email protected]
Austin Baldwin, U.S. Geological Survey, [email protected]

Abstract

Microplastics–plastic particles less than 5mm in diameter–have become a contaminant of concern in freshwater systems. However, to date, most freshwater research has focused on samples collected at the water’s surface to quantify microplastics occurrence and abundance. Little, if any, research has been done to characterize microplastic prevalence at different depths within the water column under different environmental conditions. To examine the spatial distribution in urban waterways, vertical distribution in the water column, and accumulation of microplastic particles in stream and lake sediment, water sampling was conducted across ten locations in streams and nearshore Lake Michigan. Surface and subsurface water samples were collected using 0.333 mm mesh neuston nets, and surficial sediment samples were collected at nine of the ten sampling locations. Plastic particles were observed in all 96 water samples for a total of 15,545 particles, and similarly, were observed in all nine sediment samples for a total of 4,218 particles. Fibers/lines were the most common particle type found in water (80%) and sediment (61%) samples. Comparison of surface and subsurface water sample concentrations indicated that water surface sampling alone was not a reliable predictor of the mean water column microplastic concentration.