Quantifying microplastic residence times in lakes using mesocosm experiments and transport modelling.

The microplastic residence time in lakes is a key factor controlling its uptake by lake organisms. In this work we have, for the first time, conducted a series of microplastic addition experiments in a 12 × 3 m lake mesocosm and traced its transport through the lake water column. This was combined with a 1D physically based random walk model of microplastic transport.

Heteroaggregation of PS microplastic with ferrihydrite leads to rapid removal of microplastic particles from the water column.

Microplastic (MP) particles are ubiquitous in aquatic environments. Therefore, understanding the processes that affect their removal from the water column, such as sedimentation, is critical for evaluating the risk they pose to aquatic ecosystems. We performed sedimentation experiments in which polystyrene (PS) and PS + ferrihydrite, a short-range ordered ferric (oxy)hydroxide, were analyzed in settling columns after 1 day and 1 week of settling time.