Paul Vriend , Caspar T. J. Roebroek, Tim van Emmerik

Plastic pollution in rivers negatively impacts human livelihood and aquatic ecosystems. Monitoring data are crucial for a better understanding of sources, sinks and transport mechanisms of riverine macroplastics. In turn, such understanding is key to develop effective plastic pollution prevention, mitigation and removal strategies. Riverine plastic has been observed in all compartments, of which floating macroplastic and riverbank plastic are most frequently studied. Existing riverbank plastic measurement methods vary greatly, which complicates direct comparison of data collected with different methods. We present a framework to better compare and to aid the design of riverbank plastic monitoring methods, which is based on four common elements distilled from riverbank (plastic) litter monitoring methods currently in use. This framework can be used by scientists and practitioners to find the right trade-offs between the data required to answer specific research questions, and the available resources. With this paper, we aim to provide a first step towards harmonization of riverbank (plastic) litter monitoring efforts.