Factors influencing the vertical distribution and transport of plastics in riverine environments: Theoretical background and implications for improved field study design
Jenna Brooks, Julia F. Hopkins
Abstract
Rivers have been widely recognized as important conduits and accumulation sites for plastics. Accurately describing plastic fate and transport in these systems is essential for the development of numerical models, estimating loads to oceans, and implementing effective management strategies. However, plastic transport mechanisms within fluvial environments are not well understood, and field studies often do not provide sufficient information to test analytical models of transport. Sediment transport has dynamical similarities to plastics transport in water bodies, enough to warrant further investigation into how principles from sediment transport can be used to guide the study of plastics. In this review, we summarize fundamentals from sediment transport research and their application to plastics, then use these to make suggestions of clarifying research questions and riverine field study design with the goal of generating more insightful data that can be used to understand and predict plastic fate and transport. We focus specifically on factors influencing plastic vertical distribution and movement in the water column, as variations in this direction have historically been overlooked or oversimplified in rivers.