Plastic debris in rivers

Abstract

Plastic pollution in aquatic ecosystems is an emerging environmental risk, as it may negatively impacts ecology, endangers aquatic species, and causes economic damage. Rivers are known to play a crucial role in transporting land‐based plastic waste to the world's oceans, but riverine ecosystems are also directly affected by plastic pollution. To better quantify global plastic pollution transport and to effectively reduce sources and risks, a thorough understanding of origin, transport, fate, and effects of riverine plastic debris is crucial. In this overview paper, we discuss the current scientific state on plastic debris in rivers and evaluate existing knowledge gaps. We present a brief background of plastics, polymer types typically found in rivers, and the risk posed to aquatic ecosystems. Additionally, we elaborate on the origin and fate of riverine plastics, including processes and factors influencing plastic debris transport and its spatiotemporal variation. We present an overview of monitoring and modeling efforts to characterize riverine plastic transport, and give examples of typical values from around the world. Finally, we present an outlook to riverine plastic research. With this paper, we aim to present an inclusive and comprehensive overview of riverine plastic debris research to date and suggest multiple ways forward for future research. This article is categorized under: Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems

Plastic in global rivers: are floods making it worse?

“…Additionally, it does not include intentional waste redistribution (e.g. dumping) which has been hypothesised to be substantial additional source of plastic load in rivers 1 . Furthermore, the data is described as (plastic waste generation) rates, rather than quantities, ignoring a potential build-up of plastic over time, which is inherently hard to validate.…”

“…Although most research efforts have been focussed on riverine plastic as the primary source of plastic material emitted to the oceans, the effects at the local scale can be equally, or more severe 1 . Plastic pollution has been found to signi cantly disrupt economic activities such as shing and tourism, hinder transportation over and along the river, and in some locations puts the availability of clean freshwater at risk, endangering the livelihoods of the communities living next to and depending on the river 1 . For riverine ecosystems, plastic is as detrimental as it is in the ocean, with the effects depending on the size of the debris.…”

“…The negative effect of macroplastics (> 0.5 cm) are mainly mechanical. For example, sh and mammals get entangled in the plastic and occasional ingestion can cause blockages of their intestinal tracts, enhancing mortality rates 1 . Microplastic pollution is found to break down into its initial -sometimes toxic -components 2,3 , while many of the plastic particles can also act as natural adsorbent of hydrophobic chemicals [4][5][6][7] , acting as a vector of bioaccumulation of these substances.…”

“…Of the globally produced 380 million metric tons (Mt) of plastic in 2015 8 , between 0.4 and 12.7 Mt has been reported to reach the ocean from rivers [9][10][11] . Plastic waste in the river system is potentially even higher, as many sinks have been identi ed, such as deposition on shores, deposition on and burial in riverbed sediments and accumulation within riverine species 1 .…”

An evaluation of the River-OSPAR method for quantifying macrolitter on Dutch riverbanks

“…Rivers are assumed to play a crucial role in transporting land-based plastic waste to the world's oceans (Schmidt et al, 2017). However, rivers and their ecosystems are also directly affected by plastic pollution (van Emmerik & Schwarz, 2020). To better quantify global plastic pollution transport and to effectively reduce sources and risks, a thorough understanding of sources, transport, fate and effects of riverine plastic debris is crucial.…”