Numerical modeling is an efficient tool for quantifying transport and sedimentation patterns of microplastic (MP) particles in lentic systems. To evaluate these patterns based on a specific research area we set up a three-dimensional hydrodynamic and transport model for a reservoir in Germany.

We partition the computational domain with an unstructured mesh to optimally capture the geometry of the reservoir and to adapt the mesh resolution. Thereby, shallow areas and those with steep bathymetry gradients are represented at a particularly high resolution. In vertical direction, we use a combination of z- and sigma-layers. To quantify the effects of the grid on the model results, we perform a sensitivity analysis for different horizontal and vertical mesh resolutions.

For the hydrodynamic simulations we use the Delft3D Flexible Mesh Suite (Delft3D FM). We calibrate and validate the hydrodynamic model utilizing monthly measured vertical temperature profiles for two different years. For simulating the MP transport, we rely on the sediments and morphology module of Delft3D FM. This module is based on a Eulerian approach which allows us to efficiently simulate large concentrations of MP particles.

How to cite: Jagau, L., Gilfedder, B., Fleckenstein, J., and Aizinger, V.: Three-Dimensional Hydrodynamic and Microplastic Transport Model for Lentic Systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15995, https://doi.org/10.5194/egusphere-egu24-15995, 2024.

Plastic pollution in aquatic ecosystems has become a major concern due to the adverse consequences it poses to marine and human health. Rivers are a major source of inputs of plastic waste into seas. Modelling studies in the past have estimated plastic fluxes into seas for microplastics or macroplastics. However, sources of both macro- and microplastic exports by rivers to coastal waters and their past and future trends have hardly been addressed simultaneously in a spatially explicit way (e.g., sub-basins). This includes both point sources (sewage) for microplastics from car tyre wears, personal care products, household dust and laundry as well as diffuse sources (mismanaged solid waste) for macroplastics and their fragmentation to microplastics. This study aimed to analyse the past (2010-2020) and future (2020-2100) river export of macro- and microplastics using the MARINA-Plastics model using a scenario with the rapid urbanization and high economic development under high global warming in the existing MARINA-Plastics (Model to Assess River Inputs of pollutaNts to seAs for Plastics). The model results show that estimated that globally, the annual river export of macroplastics is modelled to decrease by only 7% whereas the river export of microplastics is modelled to increase by 144% between 2010 and 2020. The large increase for microplastics is associated with increasing trends in urbanization over the period of 2010-2020. In the future, globally, the annual river exports of macroplastics are projected to increase by 118% and microplastics are projected to decrease by 8% in 2100. The sub-basins of the Atlantic, Indian and Pacific Oceans will account for more than 85% of the total river export of plastics in the future. The large increase for macroplastics is related due to poor management of waste and poor collection rates. The hotspots for macroplastic pollution in coastal waters are modelled to shift from Europe and North America to Africa and Asia in the future. Our insights could inform the design of plastic reduction policies at the international level and support the achievement of Sustainable Development Goal 14 (clean marine waters).

All authors acknowledge the support of the Water Systems and Global Change Group of Wageningen University. I. Micella is supported by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 956623 (InventWater).

How to cite: Puranik, S., Micella, I., and Strokal, M.: Global plastic export by rivers: large differences in trends between microplastics and macroplastics , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2649, https://doi.org/10.5194/egusphere-egu24-2649, 2024.

Plastic waste is globally of great concern. Rivers have the potential to transport and accumulate large amounts of plastic waste which can have harmful effects on human and animal welfare. Given the durability of plastic waste, the presence of plastic in river environments is forecasted to continue rising. As part of the project INSPIRE (Innovative Solutions for Plastic Free European Rivers), the main goal of our research is to establish a baseline for the current state of plastic litter in European rivers, with the overarching aim of facilitating the reduction of plastic waste. The initial step in achieving this reduction is the accurate modelling of plastic waste in rivers.

There is currently a lack of cohesion between plastic transport models, with models independently predicting the export of various plastic sizes (micro- and macroplastics) and in different riverine compartments (river water, riverbed sediment, riverbank). We aim to develop a single model accounting for the interaction between plastic sizes, due to degradation, and mediums, due to resuspension. Existing plastic models also generally use an annual time scale for predicting plastic concentrations in rivers. To estimate the impact of short-term climatic events, like storms and floods, on plastic concentrations in rivers, a higher temporal resolution would add value to plastic modelling.

Challenges in plastic modelling have arisen from a lack of data-availability. However, with the rise in focus on plastic research, river plastic data availability has steeply expanded, supporting a revision of current plastic modelling approaches. Our research aims to provide a more holistic approach to plastic modelling by exploring current modelling approaches to ensure an up-to-date understanding of factors affecting plastic concentrations in rivers.

Here, we revise and extend previously developed global river plastic models to also account for transport and retention. Modelling the plastic transport in rivers for all plastic sizes and in all mediums will be vital for identifying the types of plastic accumulating in the river, and in which locations. This will be imperative for the effective implementation of mitigation measures to ensure clean and safe waters for the future.

How to cite: Stibora, M., van Emmerik, T., Waldschlager, K., González Fernández, D., and Weerts, A.: Revising global river plastic transport, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7542, https://doi.org/10.5194/egusphere-egu24-7542, 2024.

We present a comprehensive assessment of micro- and mesoplastic pollution along 24 beaches of the Latvian coastline (Northern Europe, Baltic states) establishing a baseline for pollution distribution in the Baltic Sea Region. A detailed analysis of sand granulometry, hydrodynamic variables (waves and currents) and tourism intensity allowed us to understand better factors that drive plastic pollution distribution along beaches. Over 250 volunteers participated in the sample collection highlighting the importance of citizen science as a tool to support data collection.

Our findings reveal a lower concentration of micro- and mesoplastic particles in the semi-closed Gulf of Riga (0.10 particles/kg dry sand) compared to the open Baltic Sea (0.16 particles/kg dry sand). The microplastic size fraction (1-5 mm) showed a distinct cluster with higher concentrations and fiber abundance in coarser beach sands of the open Baltic Sea and eastern Gulf of Riga. We emphasize hydrodynamics as a key factor in the distribution and accumulation of microplastics, while impacts are predominantly of local scale and vary considerably across existing studies. No clear pattern of recreational activities on plastic distribution was identified. Studies elaborating on aspects like sampling season, wave energy, wind, currents, sand granulometric properties, and pollution sources are encouraged to enhance result interpretation and move towards more comparable micro-litter case studies.

Reference:

Dimante-Deimantovica I, Bebrite A, Skudra M, Retike I, Viška M, Bikše J, Barone M, Prokopovica A, Svipsta S and Aigars J (2023) The baseline for micro- and mesoplastic pollution in open Baltic Sea and Gulf of Riga beach. Front. Mar. Sci. https://www.frontiersin.org/articles/10.3389/fmars.2023.1251068/full

This work was supported by voluntary donations from the student sorority Selga, the European Regional Development Fund post-doctoral projects No.1.1.1.2/VIAA/2/18/359 and No.1.1.1.2/VIAA/4/20/733, ESF Project No. 8.2.2.0/20/I/003 “Strengthening of Professional Competence of Daugavpils University Academic Personnel of Strategic Specialization Branches 3rd Call”, and the European Economic Area (EEA) Financial Mechanism 2014–2021 Baltic Research Programme (grant EMP480).

How to cite: Retike, I., Dimante-Deimantovica, I., Bebrite, A., Skudra, M., Viška, M., Bikše, J., Barone, M., Prokopovica, A., Svipsta, S., and Aigars, J.: Micro- and mesoplastic pollution along the beaches in the open Baltic Sea and Gulf of Riga, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7586, https://doi.org/10.5194/egusphere-egu24-7586, 2024.

Microplastics (MP) enter the aquatic environment through both diffuse and point sources, and are transported through the river networks into the seas and oceans. MP threatens the aquatic ecosystems and are present in water, sediment and biota. One of the main entry paths of MP pollution are wastewater treatment plant (WWTP) effluents as well as untreated surface runoff and combined sewer overflows (CSO).

In this study, we aimed to estimate the average annual load of MP to the Seas and Oceans for 125 European catchments of different sizes.

We coupled a mass balance model modified adapted from (Bollmann et al. 2019) and a transport model representing the river network as graph theory network (GTN). The GTN is based on the HydroShed network (Lehner et al. 2008) with WWTPs inserted as additional nodes. The partitioning of MP was calculated for three sinks (sewage sludge, river sediments, load to the sea) relying on literature-derived MP concentrations from untreated surface runoff, combined sewer overflow, and WWTPs effluents. Concentrations for average discharge conditions were calculated for all stream segments using steady-state discharge data from the HydroShed database.

Based on 125 European catchments containing approximately 75% of the European WWTPs with population equivalents > 2000, we found that 77% of MP entering the river network originates from WWTP effluents, the remaining 23% is sourced from untreated surface runoff and combined sewer overflow. Of the MP that has entered the river systems, 24% are transported to seas and ocean while 76% accumulate in the river sediment. The most sensitive parameters in the model related to the loads to seas and oceans are sedimentation rates.

In a next step, the model will be updated with improved hydrological parameters. Furthermore we will apply it to future scenarios of hydro-climatic and socioeconomic conditions. As the HydroShed database is globally available, the model can be applied to other regions of the world.

References

Bollmann, U.E., Simon, M., Vollertsen, J. and Bester, K. (2019) 'Assessment of input of organic micropollutants and microplastics into the Baltic Sea by urban waters', Marine Pollution Bulletin, 148, 149-155, available: http://dx.doi.org/https://doi.org/10.1016/j.marpolbul.2019.07.014.

Lehner, B., Verdin, K. and Jarvis, A. (2008) 'New global hydrography derived from spaceborne elevation data', Eos, Transactions American Geophysical Union, 89(10), 93-94.

How to cite: Büttner, O., Schwab, A., Katterfeld, C., Schmidt, C., and Borchardt, D.: Microplastic transport in European river networks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7796, https://doi.org/10.5194/egusphere-egu24-7796, 2024.

This work presents the outcomes derived from an environmental assessment of microplastic pollution resulting from solid waste landfills in the Akmola Region, situated in North Kazakhstan. This research represents a pioneering investigation conducted on microplastics within this specific region. This study encompasses a comprehensive examination of plastic waste disposal sites across the Akmola region, with a particular emphasis on evaluating the status of the municipal solid waste management system.

To characterize the plastic content within the waste present at the landfill sites, quantitative techniques were employed. Through experimental means, the composition and fractionation of plastics within the municipal solid waste (MSW) at the landfills were determined. These data were subjected to a comparative analysis, aligning them with official statistics and previously published scientific data from both Kazakhstan and other regions globally. The methodologies employed focused on the “soft” removal of organic substances through the use of oxidants which do not damage plastics, and were tested using a water-bath therapeutic treatment. Furthermore, an analysis of soil samples taken from the landfills unveiled the ultimate retention of microplastic particles, attributed to leachate and rainwater runoff. Extracts were obtained from the subsoil samples using a density-based separation process, involving a three-step extraction followed by subsequent filtration of the resulting supernatants. In addition, the soil samples underwent examination through dry-phase particle fractional separation. The particles were meticulously enumerated and classified, and their dimensions were measured employing microscopic techniques coupled with photographic documentation. The outcomes stemming from these diverse tests will serve as fundamental input for the forthcoming numerical modeling endeavor, which aims to simulate the behavior of microplastics within both soil and water. 

How to cite: Rodrigo-Ilarri, J., Salikova, N. S., Rodrigo-Clavero, M.-E., Urazbayeva, S. E., Askarova, A. Zh., and Magzhanov, K. M.: Environmental Assessment of Microplastic Pollution Induced by Solid Waste Landfills in the Akmola Region (North Kazakhstan), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8587, https://doi.org/10.5194/egusphere-egu24-8587, 2024.

Microplastic particles (MPs) are emerging contaminants of concern that have been isolated and described in various environmental compartments. River networks can not only act as major transport pathways of MPs to the world’s oceans, but also as intermediate and long-term sinks, as well as redistributors of MPs. MP in-stream concentration and load (concentration multiplied by discharge) are key parameters when quantifying MP downstream transport and provide an indication towards potential impacts on downstream ecosystem health. MP concentrations and loads within a catchment or river network presumably vary in space and time, yet extensive studies addressing the impact of anthropogenic factors (e.g., water management practices, point source release, landuse) in conjunction with such variability on downstream MP evolution are still scarce.

Here we present key findings from two recent studies. The first study compares downstream MP concentrations and loads for the two neighboring catchments of Boulder Creek (BC) and South Boulder Creek (SBC), Colorado, USA, which vary in their population density and degree of urbanization. We collected 21 water samples (50 L, filtered through >63 µm mesh) from locations along both river channels. For each river segment we also obtained discharge information that helped us quantify MP in-stream loads and determine segment-wise load differences. Samples underwent digestion with Fenton’s reagent before potential MPs were characterized using fluorescent microscopy and Raman spectroscopy. We found that the degree of catchment urbanization influenced downstream MP patterns for both rivers, with BC (higher degree of urbanization and population density) expressing higher MP concentrations and loads than SBC. We also observed extensive downstream MP removal at certain locations where river flow was diverted for anthropogenic use in both streams. This caused a stepwise reduction of downstream MP loads and redistribution of MPs within the wider catchment.

The second study looked at the temporal evolution of in-stream MP concentrations and loads about 1000 m downstream of a wastewater treatment plant (WWTP) at a sidearm of the River Blythe, UK. The WWTP represented a point-source and was the only major MP source to the stream at our sampling location. Water samples (3x 100 L, filtered through >63 µm mesh) were collected at different intervals (monthly over an entire year, weekly over two months, hourly over four days) to better relate possible variations in MP concentrations and loads to changes in WWTP effluent discharge and to study the representativeness of snap-shot sampling. Samples were digested with Fenton’s reagent before fluorescent microscopy and Raman spectroscopy. Results indicate that temporal variability in in-stream MP load could be based on both changes in stream discharge and changes in WWTP effluent concentration, individually or simultaneously. MP loads varied by up to an order of magnitude over the course of one hour, highlighting the importance of obtaining enough representative MP data when characterizing a river system.

Our results show that spatial and temporal variability of MP concentrations and loads in rivers and river networks can be highly variable. This variability should be considered in large scale modeling exercises quantifying plastic fate and transport to the oceans.

How to cite: Schneidewind, U., Kukkola, A., Runkel, R., Murphy, S. F., Kelleher, L., Haverson, L., Sambrook Smith, G. H., Lynch, I., and Krause, S.: Spatial and temporal variability in in-stream microplastic loads can impact downstream plastic export, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9279, https://doi.org/10.5194/egusphere-egu24-9279, 2024.

Given the concerning alert about the potential high toxicity of microplastics in the environment, in recent years, significant efforts have been made to understand more about the occurrence and behavior of microplastics on Earth. Focuses of these efforts include where they are found, mainly in higher concentrations; their transport pathways; their occurrence in a diversity of organisms; their toxicity; their relationship with other pollutants; and many other questions that still need to be answered. The present work is the first one to focus on the study of microplastics in a lotic exoreic environment in the tropical Mexican Pacific region. In this study, the occurrence, temporal variation, and chemical composition of microplastics found in the surface water and bed sediment of rivers of different orders from the Baluarte River Basin were investigated. In surface waters, an average of 0.23 microplastic-like particles per liter were found during both seasons, showing no significant differences between them. During the rainy season, there was an average concentration of 0.11 particles per liter. On the other hand, in sediment, the results showed average concentrations of 139.2 and 66.7 microplastic-like particles per kilogram for the dry and rainy seasons, respectively, with significantly higher concentrations during the dry season. Most of the analyzed microparticles were fibers and had light blue and transparent colours. Polyethylene terephthalate (PET) was the most found polymer in both environmental compartments, followed by cellophane and rayon. It is concluded that, in general, the microplastics found in the fluvial system of the Baluarte River Basin may come from the discharge of domestic wastewater, agriculture, fishing, garbage dumped on land, as well as the construction of a hydrological infrastructure in the area. For future more detailed studies, it is recommended to increase the number of sampling sites at varying distances from human settlements and to explore better methods for microplastic separation. If possible, it would be interesting to implement control measures in first-order rivers of the Baluarte River Basin.

How to cite: Green Ruiz, C. R., Hernández-Angeles, J., and Rivera-Hernández, J. R.: Microplastics in water and bed sediments from the Baluarte River Basin: Occurrence, behavior and composition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11798, https://doi.org/10.5194/egusphere-egu24-11798, 2024.

Plastic has become an invasive material in modern human lifestyle and is heavily relied upon as an essential resource. It is identified as one of the chief environmental problems. Although identified primarily into marine environments, the main source of the plastics is from land and is discharged into our shores via rivers. To be able to lessen their impacts into the ocean, it is important to understand how to reduce their production upstream. This research is focussing on the fate of the secondary microplastics (MP) from when they leave the household with the greywaters to when they are released via the WWTP (wastewater treatment plant) discharges into our urban rivers.

The household laundry of synthetic textiles has been recognised as one of the largest sources of MP production. This counts for most of the MPs leaving our home via greywaters to reach urban WWTPs. Consequently, the study has focussed on MPs released from 24 washing machine loads, consisting of well-catalogued and weighed various combinations of synthetic garments, under “normal wash conditions”. It was determined that an average load can produce up to 93,000 MP fibres per kg, but it was found that heavier loads released fewer MP fibres. Using a full washing load can reduce the number of fibres produced by up to 70%.

To estimate the release of MPs into freshwater rivers from WWTPs, six discharges from urban plants from middle size towns around Greater London have been sampled and analysed. It was found that although MP quantities are very high the numbers vary greatly due to the age and the size of those sites, but also the technique that is used. It results in a range between 0.5 and 18 million MP per hour being released. This highlights that WWTPs are not advanced enough to remove MP pollution, making these discharges the main source into the freshwater environment.

Furthermore, the MP release from plant discharges into rivers is not the main secondary source as up to 98% of the MPs passing through WWTPs might end up as sludge that can later be applied to improve agricultural land for higher crop yields. This creates a major source of MP fibres into our rural rivers upstream of the urban hubs. Not only does this introduce microplastics to terrestrial habitats but it also creates a direct secondary pathway for microplastics to enter surface waters. This study highlights the urgency to update wastewater treatment and disposal practices to tackle the various issues of fibres getting into surface and groundwaters.

How to cite: Grassineau, N., Eldridge, L., and Rossouw, S.: The course of microplastics before and after UK WWTPs and their release into the environment., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19529, https://doi.org/10.5194/egusphere-egu24-19529, 2024.

Microplastic (MP) particles are assumed to be potentially harmful to organisms in the hydrosphere. To better assess the exposure and the associated risk it is essential to quantify the transport and sedimentation behavior of MP particles in aquatic environments.

Using the Delft3D Flexible Mesh Suite we set up a three-dimensional hydrodynamic and MP transport model for lakes and reservoirs. Our focus is on modeling polymers with different densities and particle sizes to identify patterns of particle residence time and sedimentation. The reservoir Großer Brombachsee in Germany serves as the research site with realistic forcings and boundary conditions.

We present first results for horizontal and vertical distribution patterns for different polymer types. We found that the distribution of MP in the computational domain is strongly affected by both particle density and particle size. Smaller, lighter particles are spread over the entire horizontal extent of the reservoir, but particles of higher density or of larger size settle within a limited area around the inflow location, indicating a much higher settling velocity.

How to cite: Aizinger, V., Jagau, L., Gilfedder, B., and Fleckenstein, J.: Modeling the transport and residence time of microplastic particles in lakes and reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18531, https://doi.org/10.5194/egusphere-egu24-18531, 2024.

Rivers play a substantial role in plastic pollution transport and storage but the transport processes that determine macroplastic fate in the riverine environment are not fully understood yet. Usually it is unknown when and where specific plastic litter items entered the environment, therefore macroplastic transport is often studied via e.g. GPS trackers. However, the July 2021 flood provided an unique opportunity of spilled macroplastic items, with clearly known time and space of emission.
In July 2021 severe floods affected multiple European river catchments, including the Meuse catchment in Belgium. A dairy company located at the Meuse tributary Vesdre was flooded, with parts of their facilities and a lot of material washed away. Among the washed away material was also ~8 million empty dairy packages ("buttertubs"), which have a printed ID code that can be traced to their emission point. During macroplastic sampling immediately after the flood event, and in the following two years, we found 617 of these buttertubs along the Dutch section of the Meuse river (~66 - 328 km downstream of the dairy company). We used the buttertubs as tracers for macroplastic transport in the period that includes the flood event, and the following two years. Within 20 days of the flood event, some of the buttertubs were transported ~328 km and were found close to the Rhine-Meuse-Delta. However, the majority of buttertubs was transported less than 100 km within these 20 days, with an average transport distance between 9.75 - 18.25 km/day. Over the following two years the average transport distance decreased to 0.23 km/day. Which could imply that the buttertubs either were only transported across smaller distances in the following two years, or even not remobilized at all after being deposited during the flood event. Some of the buttertubs we also collected, and we investigated their mass and fragmentation development over time. 
In this unique opportunistic study, we found that the buttertubs mean transport distance moved downstream over the course of two years. The majority of them however, was deposited rather close to their emission point, even given the extreme flood situation. 

How to cite: Hauk, R., van der Ploeg, M., Teuling, A. J., de Winter, W., and van Emmerik, T. H.: Buttertubs spilled during the July 2021 flood as plastic transport tracers in the Dutch Meuse river, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1759, https://doi.org/10.5194/egusphere-egu24-1759, 2024.

To tackle the accumulation of plastic in the open oceans and along the shorelines, it is necessary to identify and understand its input paths. With more than 4smaller coastal systems draining into the global oceans, this is a complex task. A global model representing a plethora of different systems is one way to approach this problem.

For this purpose we improved the global river model presented in Meijer et al., 2021 which is using multiple datasets such as topography, land cover, runoff, precipitation, wind, population density, landfills, dams and mismanaged plastic waste per country to estimate the magnitude of the input of plastic into the oceans. This is achieved by a mouth-2-source algorithm that originates from each river mouth. How far the influence of a given network reaches inland is dependent on the discharge within it and is parametrized with an abstract, global parameter, γ. The value of the latter can be calibrated using an analysis of both Eulerian and Lagrangian in-situ river plastic transport data from different river systems worldwide.

Our analysis highlights the importance of plastic transport experiments with high data-density. The model results put the global plastic input into the ocean close to 500 kt/yr and indicate that the influence of the numerous smaller coastal catchments needs to be taken into account  With this model we are further able to identify river systems that interesting for targeted action.

How to cite: Ebner, R., Mani, T., and Lebreton, L.: The Best of Both Worlds – Combining a Revised Global River Model to In-Situ River Plastic Transport Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17345, https://doi.org/10.5194/egusphere-egu24-17345, 2024.

Plastic pollution has been receiving considerable attention from scientists, policy makers and the public during the last few decades. Though some models succeeded to simulate transport and fate of plastic debris in freshwater systems (Meijer et al., 2021), a complete model is under development to elucidate the whole picture of plastic dynamics in continental scale. Previously, process-based eco-hydrology models, NICE (National Integrated Catchment-based Eco-hydrology)-BGC (BioGeochemical Cycle) (Nakayama, 2017), was applied to evaluate biogeochemical cycling in river basins ranging from local/regional to continental/global scales. Recently, the author linked NICE-BGC to plastic debris model that accounts for transport and fate of plastic debris (advection, dispersion, diffusion, settling, dissolution and biochemical degradation by light and temperature), and applied this new model to regional scale (Nakayama and Osako, 2023a) and global major rivers (Nakayama and Osako, 2023b). NICE-BGC was also improved to include the mass budget in water and bed sediment in order to show the seasonal variations of plastic fluxes. In this study, NICE-BGC was further extended to incorporate biofouling (with algae and phytoplankton) and heteroaggregation (with suspended particulate matter) to improve the accuracy of global plastic dynamics in global river basins and the amount of plastic flows from land into rivers and finally into the ocean. Model simulated size distribution of plastics in water and riverbed sediment of global major rivers and showed the difference of effect of biofouling and heteroaggregation in each river. In addition, the simulated result showed that flood events have a great impact on plastic mobilization and its high intra-annual variability mainly caused by settling, resuspension, and bedload transport (Hurley et al., 2018; van Emmerik et al., 2019). These results aid development of solutions and measures to reduce plastic input to the ocean, and help to quantify magnitude of plastic transport under climate change.

References

Hurley, E., et al. 2018. Nature Geoscience, 11, 251-257, doi:10.1038/s41561-018-0080-1.

Nakayama, T. 2017. Journal of Geophysical Research: Biogeosciences, 122, 966-988, doi:10.1002/2016JG003743.

Nakayama, T., Osako, M. 2023a. Ecological Modelling, 476, 110243, doi:10.1016/j.ecolmodel.2022.110243.

Nakayama, T., Osako, M. 2023b. Global and Planetary Change, 221, 104037, doi:10.1016/j.gloplacha.2023.104037.

van Emmerik, T., et al. 2019. Scientific Reports, 9, 13549, doi:10.1038/s41598-019-50096-1.

How to cite: Nakayama, T.: Towards improvement to understand plastic dynamics in global rivers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3263, https://doi.org/10.5194/egusphere-egu24-3263, 2024.