Rivers as Plastic Reservoirs

Abstract

Land-based plastic waste, carried to the sea through rivers, is considered a main source of marine plastic pollution. However, most plastics that leak into the environment never make it into the ocean. Only a small fraction of plastics that are found in the terrestrial and aquatic compartments of river systems are emitted, and the vast majority can be retained for years, decades, and potentially centuries. In this perspective paper we introduce the concept of river systems as plastic reservoirs. Under normal conditions, hydrometeorological variables (such as wind, runoff and river discharge) mobilize, transport and deposit plastics within different river compartments (e.g., riverbanks, floodplains, lakes, estuaries). The emptying of these plastic reservoirs primarily occurs under extreme hydrological conditions (e.g., storms, floods). In this paper we specifically focus on the retention mechanisms within different river compartments, and their effect on the fate of the plastics that are accumulated on various timescales. We aim to introduce the concept of rivers as (long-term) sinks for plastic pollution, and provide suggestions for future research directions.

Will it Float? Rising and Settling Velocities of Common Macroplastic Foils

“…This results in an accumulation of plastic waste in the environment, such as terrestrial, riverine, and marine ecosystems. 1 − 4 …”

Pilot monitoring drijvend zwerfafval en macroplastics in rivieren: jaarmeting 2021

“…Deze resultaten suggereren dat het meeste zwerfafval dat benedenstrooms van de rivieren wordt gemeten in Nederland de rivier inkomt, of dat benedenstrooms veel zwerfafval en macroplastics accumuleren. Dit is deels te verklaren door de getijdedynamiek, die waarschijnlijk resulteert in een lage emissie van zwerfafval en plastic naar zee (van Emmerik et al, 2022a). Dit beeld wordt bekrachtigd door de massabalans (Tabel 7).…”

“…Het is daarom aannemelijk dat ook hier extra materiaal de rivieren inkomt. Daarnaast zorgt de getijdendynamiek voor complexe stroming, wat ervoor zorgt dat relatief weinig zwerfafval en macroplastic het systeem daadwerkelijk verlaat(van Emmerik et al, 2022a;Meijer et al, 2021). De getijdegebieden zouden daarom kunnen werken als (tijdelijke) accumulatiezones.…”

Underwater Macroplastic Detection Using Imaging Sonars

“…Globally, plastic pollution is a major problem with adverse effects for freshwater and marine ecosystems (Thompson et al, 2004;Cole et al, 2013;Free et al, 2014;Lechner et al, 2014;Schmidt et al, 2017;Lau et al, 2020;Van Emmerik et al, 2022a). Once plastic is produced and discarded on land, a large amount is retained in riverine sinks while only a fraction ends up in marine ecosystems via riverine transport (Moore et al, 2011;Lebreton et al, 2017;Schmidt et al, 2017;D'Hont et al, 2021;Meijer et al, 2021;Van Emmerik et al, 2022b). In rivers, plastics have been observed accumulating in sediments and vegetation of banks and floodplains, transported in the riverbed and floating or suspended in the water column (Schwarz et al, 2019;Van Emmerik and Schwarz, 2019;Van Emmerik et al, 2022b).…”

“…Once plastic is produced and discarded on land, a large amount is retained in riverine sinks while only a fraction ends up in marine ecosystems via riverine transport (Moore et al, 2011;Lebreton et al, 2017;Schmidt et al, 2017;D'Hont et al, 2021;Meijer et al, 2021;Van Emmerik et al, 2022b). In rivers, plastics have been observed accumulating in sediments and vegetation of banks and floodplains, transported in the riverbed and floating or suspended in the water column (Schwarz et al, 2019;Van Emmerik and Schwarz, 2019;Van Emmerik et al, 2022b). However, there is a data deficiency for all of the plastic sources and sinks in rivers due to differing or lacking long-term monitoring strategies (Schöneich-Argent et al, 2020;Van Emmerik et al, 2022a).…”