DISTRIBUTION AND MOVEMENT OF MICROPLASTIC IN URBAN STREAMS
Plastic production and disposal has accelerated since the 1950s, generating global accumulations of plastic litter. Rivers are considered a conduit of microplastic (< 5 mm) to oceans, but the capacity for rivers to retain, transform, and redistribute microplastic is unknown. We measured microplastic retention and transport rates in 3 Chicago-area streams by adapting organic matter 'spiraling' methods. We quantified microplastic and fine particulate organic matter (FPOM) abundance by habitat (surface water, water column, benthos) at 3 points in 100 m reaches of each stream. We calculated downstream velocity, turnover rate, spiraling length, and index of retention for microplastic and FPOM. Downstream velocity and indices of retention were similar between microplastic and FPOM. However, the slow rate of plastic biodegradation results in a much lower turnover rate and longer spiraling length for microplastic relative to FPOM. Overall, microplastic is quickly retained within streams, but is long-lived enough to undergo many more 'spirals' downstream than organic particles. Spiraling metrics have not previously been used to quantify microplastic movement in streams, and these data are needed to contribute to global plastic budgets.
Anna Vincent (Primary Presenter/Author), Loyola University Chicago, firstname.lastname@example.org;
Timothy Hoellein (Co-Presenter/Co-Author), Loyola University Chicago, email@example.com;