The key role of surface tension in the transport and quantification of plastic pollution in rivers
Publication date
2022-10-28
Document type
Forschungsartikel
Author
Organisational unit
Scopus ID
Publisher
Elsevier
Series or journal
Water Research
ISSN
Periodical volume
226
Article ID
119078
Is referenced by
Peer-reviewed
✅
Part of the university bibliography
✅
Language
English
Keyword
Macroplastic
Plastic concentration
Plastic transport
Surface transport
Surfaced plastic
Suspended transport
Abstract
Current riverine plastic monitoring best practices mainly consider surface observations, thus neglecting the underlying distribution of plastics in the water column. Bias on plastic budgets estimations hinders advances on modelling and prediction of plastics fate. Here, we experimentally disclose the structure of plastics transport in surface water flows by investigating how thousands of samples of plastics commonly found in fluvial environments travel in turbulent river flows. We show for the first time that surface tension plays a key role in the transport of plastics since its effects can be of the same magnitude as buoyancy and turbulence, therefore holding a part of the dispersed buoyant plastics captive by the water surface. We investigate two types of transport; surfaced plastics (surface tension-turbulence-buoyancy dominated), in contact with the free surface, and suspended plastics (turbulence-buoyancy dominated). We prove that this duality in transport modes is a major source of error in the estimation of plastic budgets, which can be underestimated by 90 % following current, well-established monitoring protocols if sampling is conducted solely in the water surface. Based on our empirical findings, we optimize physics-driven monitoring strategies for plastic fluxes in rivers, thereby achieving over a ten-fold reduction of the bias and uncertainty of riverine plastic pollution estimates.
Description
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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Published version
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