Abundance of plastic debris across European and Asian rivers

Abstract

Plastic pollution in the marine environment is an urgent global environmental challenge. Land-based plastics, emitted into the ocean through rivers, are believed to be the main source of marine plastic litter. According to the latest model-based estimates, most riverine plastics are emitted in Asia. However, the exact amount of global riverine plastic emission remains uncertain due to a severe lack of observation. Field-based studies are rare in numbers, focused on rivers in Europe and North America and used strongly varying data collection methods. We present a harmonized assessment of floating macroplastic transport from observations at 24 locations in rivers in seven countries in Europe and Asia. Visual counting and debris sampling were used to assess (1) magnitude of plastic transport, (2) the spatial distribution across the river width, and (3) the plastic polymer composition. Several waterways in Indonesia and Vietnam contain up to four orders of magnitude more plastic than waterways in Italy, France, and The Netherlands in terms of plastic items per hour. We present a first transcontinental overview of plastic transport, providing observational evidence that, for the sampled rivers, Asian rivers transport considerably more plastics towards the ocean. New insights are presented in the magnitude, composition, and spatiotemporal variation of riverine plastic debris. We emphasize the urgent need for more long-term monitoring efforts. Accurate data on riverine plastic debris are extremely important to improve global and local modeling approaches and to optimize prevention and collection strategies.

The Way of Macroplastic through the Environment

“…These data can be compared with studies carried out at 24 sites along rivers in seven different countries in Europe (Italy, The Netherlands, France) and Asia (Vietnam, Indonesia, Thailand, Malaysia), in which the proportion of transported MaP was determined. The averaged values are highest for South-East Asia (1000-10,000 MaP items/h) and significantly lower for Europe (100-1000 MaP items/h), which is due to the heavy pollution of the rivers in Indonesia and Vietnam [125]. This is consistent with the quantities of superficial MaP measured by Vriend et al (2020) [5] in the Rhine, accounting for 10-75 items/h.…”

Manila River Mouths Act as Temporary Sinks for Macroplastic Pollution

“…With the plastic flux p [items min −1 ] for each segment i, the total counted plastic items C [items] in section i, and the measurement duration T [min] at section i. The total plastic flux over the entire river width P is expressed in items hour −1 , the most commonly used unit (e.g., Castro-Jiménez et al, 2019;van Calcar and van Emmerik, 2019;Schirinzi et al, 2020). Plastic flux in downstream direction is noted as positive, and plastic flux in upstream direction is noted as negative.…”

Plastic in global rivers: are floods making it worse?

“…An increasing number of studies estimated river plastic transport, accumulation and emissions into the ocean on local, national and global scales [9][10][11][12][13] . The temporal dynamics of the plastic load is less well understood, as most observational studies are single instance measurements or measurements over a very short period of time 12 . The rst observational studies over longer periods have hinted at a strong link between discharge and the amount of plastic in the river [14][15][16] .…”