The unknown fate of macroplastic in mountain rivers

Liro, Maciej; Emmerik, Tim van; Zielonka, Anna; Gallitelli, Luca; Mihai, Florin‐Constantin

doi:10.1016/j.scitotenv.2022.161224

Cited by 20 publications

(19 citation statements)

References 37 publications

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“…Regardless of the tracking method used, short-term experiments may be still useful for quantifying macroplastic fragmentation occurring during floods, which are previously suggested as factors enhancing mechanical fragmentation of macroplastic in rivers 5,8 . It seems that the proposed methodology can be useful not only for recording macroplastic fragmentation in other river types 8 but also in other environments on Earth where macroplastic transport and its mechanical interactions with water and sediments occur, such as seas or beaches 15 .…”

Section: Discussion and Future Outlookmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Field-based information on the rates of macroplastic fragmentation in different environments is, however, very limited 1,2,3 especially for rivers 4,5,6,7,8 . Recent works have, however, hypothesised that river channels can operate as hot-spots of macroplastic fragmentation because of constant movement of water and sediments in this zone which can favour mechanical interactions of macroplastic with water, sediments, and riverbeds 5,8 . The intensity of these interactions can be particularly high in the case of mountain river channels, where high-energy water and sediment transport coincide with the presence of numerous physical obstacles such as boulders, bedrock, and large wood within the river channel 8 .…”

Section: Introductionmentioning

confidence: 99%

“…Field experiments exploring this process have not yet been conducted. However, obtaining direct information about the rate of macroplastic fragmentation in mountain rivers is crucial for quantifying the production of secondary microplastics in these environments and evaluation of related risks to their river biodiversity 9,10 , quality of resources they provide for human populations (e.g., water resources 11 ), and understanding the extent to which they can be transported downstream to lowland rivers and oceans 5,8 .…”

Section: Introductionmentioning

confidence: 99%

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Experimental method for quantifying macroplastic fragmentation in rivers

Liro,

Zielonka,

Mikuś

2024

Preprint

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Direct field measurements of macroplastic fragmentation during its transport in rivers are unavailable, and there is no method to perform such measurements. Recent theoretical works have hypothesised that river channels may be hotspots of macroplastic fragmentation. Here, we propose a methodology for quantifying riverine macroplastic fragmentation by conducting repeated measurements of tagged macroplastic items' mass before and after their transport in the river. A 52-65-day experimental test of the proposed methodology allowed us to provide the first quantification of fragmentation of 1-liter PET bottles during their transport in a mountain river channel. We calculated the mass loss of tracked bottles (n=43), ranging from 0.025 grams/year (0.07%/year) to 1.0 gram/year (3%/year), with a median of 0.26±0.04 grams/year (0.78%/year), and the rate of bottle surface degradation, ranging from -0.29 μm/year to -11.88 μm/year (median = 3.77±0.43 μm/year). These results suggest that the total fragmentation time for a PET bottle under conditions represented by our experiment (low to medium flow) ranges from 33.63 years to 332.81 years (median = 128.92±31.07 years). Our methodology can be flexibly adapted to quantify macroplastic fragmentation in various types of rivers and other environments where macroplastic is transported

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Section: Discussion and Future Outlookmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental method for quantifying macroplastic fragmentation in rivers

Liro,

Zielonka,

Mikuś

2024

Preprint

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“…There are numerous examples of riverine macroplastic waste with film shapes, which enter rivers as packaging, buildings, and agricultural litters. Such items are frequently trapped in obstacles present in the inundated parts of river channels (e.g., boulders, wood jams) (Liro et al, 2022(Liro et al, , 2023 or riparian vegetation (Cesarini and Scalici, 2022), providing them with ideal exposure to both mechanical (via water movement, wind, rain) and biochemical factors of fragmentation (via photo-oxidation) (Fig. 4).…”

Section: Mass-to-surface-area Ratiomentioning

confidence: 99%

Macroplastic fragmentation in rivers

Liro¹,

Zielonka²,

Emmerik³

2023

Preprint

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The process of macroplastic (>0.5 cm) fragmentation results in the production of smaller plastic particles (micro- and nanoplastics), which threaten biota and human health and are difficult to remove from the environment. The global coverage and long retention times of macroplastic waste in fluvial systems (ranging from years to centuries) create long-lasting and widespread potential for its fragmentation and the production of secondary micro- and nanoplastics. However, the pathways and rates of this process are unknown, which constitutes a fundamental knowledge gap in our understanding of macroplastic fate in rivers and the transfer of produced microparticles throughout the environment. To set the stage for future research aiming to fill this gap, we present a conceptual framework which identifies two types of riverine macroplastic fragmentation controls: intrinsic (resulting from plastic item properties) and extrinsic (resulting from river characteristics and climate) processes. First, based on the existing literature, we identify the intrinsic properties of macroplastic items that make them particularly prone to fragmentation (e.g., the film shape, low polymer resistance, previous weathering). Second, we propose a conceptual model showing how extrinsic controls can modulate the intensity of macroplastic fragmentation in perennial and intermittent rivers. Using this model, we hypothesize that the inundated parts of perennial river channels—as specific zones exposed to the constant transfer of water and sediments—provide particular conditions that accelerate the physical fragmentation of macroplastics resulting from their mechanical interactions with water, sediments, and riverbeds. The non-inundated parts of perennial river channels provide conditions for biochemical fragmentation via photo-oxidation. In intermittent rivers, the whole channel zone is hypothesized to favor both the physical and biochemical fragmentation of riverine macroplastics, with the dominance of the mechanical type during the wet season. Our conceptualization aims to support future experimental works quantifying macroplastic fragmentation rates in different types of rivers.

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