• Novel monitoring methods, including advanced techniques (e.g. remote sensing, multi/hyperspectral cameras, acoustic sensors, artificial intelligence);
• Monitoring strategies, including large-scale and long-term efforts, and citizen science approaches;
• All plastic size ranges, from nano to macro;
• Baseline studies to assess current plastic pollution levels;
• Long-term trends or recent discoveries based on plastic monitoring data.
With this session we aim to bring together scientists that work on novel approaches to provide reliable data on environmental plastic pollution.
Orals: Tue, 5 May, 08:30–10:15 | Room -2.31
Quantifying floating macrolitter in rivers and seas contributes to designing effective mitigation strategies and evaluating environmental policies. This field has undergone a significant transformation over the last years, transitioning from fragmented local studies to large scale harmonized monitoring. This evolution is rooted in the first systematic effort to quantify riverine litter inputs, which established visual observation and the use of a mobile App as a robust and accessible method (González-Fernández & Hanke, 2017).
Building upon these foundations, the monitoring landscape has been further refined through scientific publications and the development of European and international guidelines. Such guidelines provide the scientific and methodological basis to ensure that data collected across different regions and basins are comparable and representative. Here we review data available in the literature and the use of the existing guidelines at global level.
In 2025, the European Commission has launched the new JRC Floating Litter Monitoring App. This digital tool integrates the official Joint List of Litter Categories and allows for real-time, geo-referenced data acquisition in both riverine and marine environments. Beyond its technical capabilities, the app is designed to be an effective tool for facilitating standardized reporting and data management. By bridging the gap between field observations and global databases, it enables a consistent evaluation of pollution levels at a global scale. This presentation will highlight how the integration of harmonized protocols and user-friendly technology can empower a global network of observers, providing the reliable data needed to support international environmental regulations and the fight against plastic pollution.
How to cite: González-Fernández, D., Ruiz-Orejón, L. F., and Hanke, G.: Floating Macrolitter Monitoring: From initial harmonization to a Global Reporting Tool, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10445, https://doi.org/10.5194/egusphere-egu26-10445, 2026.
Plastic pollution in soils and floodplains is a critical but understudied issue, with scarce field data on abundance, transport and remediation. Rivers are key pathways transporting plastics of all sizes, yet long-term and large-scale monitoring data remain scarce. To preserve and restore the ecosystem services floodplains provide, they must be protected from plastic pollution and its negative consequences for humans and nature.
We conducted a large-scale monitoring campaign along the entire course of one of Europe’s last undammed rivers (Vjosa, Albania). Its course is little anthropogenically influenced and allows unique insights into macro- and microplastic hotspots in floodplain. At these hotspots, novel retention modules developed at the HTWD can be deployed as nature-based solution to prevent plastic pollution in floodplains.
We tested a novel transect-based sampling/monitoring approach for macro- and microplastics to gain insights on plastic transport and accumulation along the Vjosa River. We considered vegetation succession zones and geomorphology, both representing flood dynamics. Data collection included vegetation species and distribution, high-resolution digital elevation models through photogrammetric drone flights to resolve floodplain topography and infer associated flood dynamics, macroplastic and sediment sampling for microplastic analysis. We analysed macroplastics with a portable FTIR as well as ATR-FTIR. We processed sediments with a validated in-house protocol consisting of density separation (CaCl2, density: 1.45 g/cm³), and Fenton oxidation to extract microplastics, followed by DSC (Differential Scanning Calorimetry) and TED-GC/MS (Thermal Extraction-Desorption GC/MS) for mass-based microplastic analysis. Preliminary results show macroplastic accumulation in floodplain depressions and the standing woody succession zones, likely liked to vegetation structure. We expect similar trends for microplastics and overall higher abundances from upstream to downstream, where sedimentation in general increases.
In parallel, we tested novel wooden retention modules (30x30x10 cm) as a nature-based solution filled with different substrates and vegetation densities of willows and grass species. Laboratory flooding experiments with microplastic spiked water (low-density polyethylene and polyamide, 500 – 800 µm) demonstrated polymer type-specific retentions with higher rates for PA (mean: 91.4 %) than LDPE (mean: 18.4 %). The vegetation density and diversity proved to be one of the major factors in retention efficiency. Therefore, the retention modules are a promising solution to minimize microplastic input in floodplain soils.
Our study delivers one of the first comprehensive datasets on plastic pollution in a near-natural European river system, integrating vegetation, geomorphology and high-resolution elevation models. By combining large-scale monitoring with mitigation testing, we advance reliable approaches to assess and reduce plastic pollution across the geosphere. This not only directly supports conservation and management of the Vjosa River National Park and UNESCO Biosphere Reserve, and contributes rare field data to the global database of plastic pollution, but also highlights the ecosystem services of natural floodplains in plastic pollution retention, fosters their preservation, and demonstrates pathways to substitute their functions through retention modules where they are degraded. In doing so, our approach provides a concrete, nature-based solution that can be scaled to other river systems, thereby contributing to tackling the global plastic crisis.
How to cite: Seidel, P., Gjashta, X., Johannes, M., Sabrina, S., Sajmir, B., Danilo, S., Clara Rosa, G., Arne, C., and Kathrin, H.: From Monitoring to Action: A New Sampling Strategy and Retention Modules for Plastics in Floodplains – Tested at the Vjosa River, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1119, https://doi.org/10.5194/egusphere-egu26-1119, 2026.
The definition of assessment methods for determining the good environmental status of beaches with respect to marine litter is an essential requirement for the implementation of the European Marine Strategy Framework Directive. Government monitoring programmes, citizen-science initiatives, and the scientific community are generating large amounts of data on marine-litter abundance, particularly on macrolitter and especially on beaches. Interestingly, these litter counts are reported in a specific and detailed manner by item categories, enabling the exploration of potential pollution sources. However, most existing assessments rely on the total count of litter categories, without considering their heterogeneity or origin. This approach limits the development of effective, source-focused management strategies.
The present study introduces an assessment based on a set of seven indicators related to marine-litter sources, accounting for both the potential origins and size classes of different litter categories. We refer to this integrated approach as the Beach Litter Footprint. This multidimensional analysis leads a more comprehensive assessment, as it allows impacts to be weighted according to the typology and origin of the litter found at each location.
The applicability of the Beach Litter Footprint was examined through a large-scale analysis along the coastline of the Iberian Peninsula and its surrounding environment, namely the North African continent, the Azores, Madeira, and the Canary Islands in the Atlantic Ocean, and the Balearic Islands in the Mediterranean Sea. The choice of this region of interest (ROI) for the proof of concept was based on two factors. First, the availability of data in this area, especially from citizen-science activities; and second, the wide environmental diversity of the region, comprising two distinct water masses (the Atlantic Ocean and the Mediterranean Sea), two continents with relevant socioeconomic differences, abundant archipelagos, and major coastal cities and rivers.
The Beach Litter Footprint clearly identified contamination hotspots and well-preserved areas, revealing previously unreported patterns regarding the origin and distribution of litter at both local and regional scales. Our analysis also highlighted the remarkable value of citizen science for this type of assessment. The Beach Litter Footprint provides a comprehensive and easily replicable diagnostic tool based on routine beach-litter monitoring data. Unlike other indicators, it provides a detailed view of both the mass and the origin of beach-litter pollution, helping decision-makers to design source-targeted mitigation strategies.
How to cite: Ceballo, J. and Cozar, A.: A Methodological Framework for Defining Beach Litter Footprints: Application in the Iberian Peninsula, Macaronesia, and the Balearic Islands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1193, https://doi.org/10.5194/egusphere-egu26-1193, 2026.
Deep learning-based computer vision methods are widely used to detect and quantify floating macroplastic litter in rivers, enabling accurate assessments of plastic pollution by automatically processing images and videos. However, these methods typically rely on large amounts of annotated data for supervised learning (SL), and the manual labeling work is costly and time-consuming. This hinders broad model generalization, a key requirement for robust computer vision systems for long-term and large-scale litter monitoring.
To overcome this challenge, we propose a Vision-Language Model (VLM)-based method for detecting floating litter, without labeled images for model training. Recent advances in Generative AI, particularly VLMs, have revolutionized artificial intelligence by enabling rich semantic understanding across modalities. Pre-trained on millions to billions of image-text pairs, VLMs effectively learn visual representations from the natural language supervision, thereby enabling robust cross-modal understanding and generalization. This broad pre-training also allows VLMs to achieve remarkable zero-shot generalization performances in many domain-specific applications, even without domain-specific labeled images for SL.
We demonstrate the effectiveness of our methodology using multiple VLMs (e.g., DeepSeek-VL2 and OpenCLIP) on images collected from canals and waterways in the Netherlands and South East Asia. We conduct a comprehensive comparison with conventional SL approaches using multiple deep learning architectures (e.g., Vision Transformer, ResNet, and DenseNet). The results indicate that our method achieves robust zero-shot generalization performance.
Based on these results, we suggest stakeholders (e.g., researchers, consultants and governmental organizations) to consider VLM-based methods to develop robust systems for targeted long-term floating litter monitoring, while minimizing the cost of collecting labeled data.
How to cite: Zhang, C., Jia, T., J. Franca, M., Lofty, J., Rebai, D., and Ehret, U.: Vision-Language Models for Floating Litter Detection, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8285, https://doi.org/10.5194/egusphere-egu26-8285, 2026.
Rivers are major pathways for transporting land-based plastic pollution to the ocean, with much of this material accumulating along nearby coastlines. To address this issue, The Ocean Cleanup deploys river interception systems worldwide to halt plastics before they reach the sea. However, the extent to which river interception reduces coastal pollution has not yet been empirically demonstrated. In this study, we introduce a standardized impact‑mapping approach that integrates (i) baseline assessments of beached plastic composition, (ii) quarterly beach monitoring, and (iii) biannual characterization of intercepted riverine plastics following the deployment of interception technologies. Using the first year of data from two pilot locations – the Motagua River (Guatemala) and the Klang River (Malaysia) – we show that plastic composition exhibits substantial spatial and temporal variability in both riverine and coastal environments. Moreover, periods of elevated riverine plastic flux correspond to increased concentrations of beached plastics. Item‑level characteristics – including country of origin, age, and degradation state – provide additional insight into whether stranded plastics stem predominantly from local terrestrial inputs or from longer‑residence marine sources. As we expand this program to several further global locations, these results will support improved calibration of river‑to‑coast transport models and strengthen our ability to quantify and evaluate the coastal pollution impact of The Ocean Cleanup’s river interception technologies.
How to cite: Novikova, E., Wolter, H., Lebreton, L., and Mani, T.: Mapping the Impact of River Plastic Interception Across River–Coast Systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23246, https://doi.org/10.5194/egusphere-egu26-23246, 2026.
This study is inspired by the Plastic Cup’s unique “bottle mail” collection, an extensive archive of marked bottles gathered over more than a decade of river cleanups. These personal messages, carried by rivers across years and borders, motivated us to rely on public engagement to better understand the dynamics of plastic pollution in freshwater systems. In response to this environmental challenge, our research combines citizen science, advanced tracking technologies, and long-term datasets to study both short- and long-term plastic bottle mobility in rivers of the Danube Basin. The bottle-tagging citizen science programme engages schools, NGOs, and local communities through a catch-and-release methodology. Following the long-standing tradition of the “message-in-a-bottle” approach, plastic bottles collected from the environment are fitted with unique identifiers then reintroduced into the wild. As of the submission of this abstract, 184 bottles have been tagged in 7 Danube countries, with 7 confirmed re-captures. To compensate for the inherent limitations of citizen science, a professional component was added to the methodology through GPS-based tracking. Plastic bottles equipped with GPS transmitters are deployed to monitor riverine transport in near real-time, enabling high-resolution mapping of movement and accumulation patterns over days and weeks. These datasets offer insights into flow-dependent transport, hydrological event impacts, and potential hotspot areas requiring intervention. Integrating citizen-generated and GPS-based data supports a more comprehensive understanding of short- versus long-term transport dynamics. As an ongoing initiative, data collection is not complete yet. Hereby we present partial results with the intention to inspire the scientific community as well as to increase participation in citizen science efforts while contributing to a multidimensional understanding of plastic transport in rivers.
How to cite: Molnar, A. D. and Gyalai Korpos, M.: Messages in Bottles – Short and Long-Term Tracking of Plastic Bottles in Riverine Systems with a Multidisciplinary Approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22014, https://doi.org/10.5194/egusphere-egu26-22014, 2026.
Rivers play a key role in the global distribution of anthropogenic litter. Accurate and reliable monitoring data are essential to design effective litter reduction and mitigation strategies. One common approach used to monitor macro- and mesolitter (>0.5 cm) in rivers is through visual riverbank litter sampling, in which observers manually collect, count and categorize items deposited on riverbanks. While monitoring efforts are scaling up to meet growing demand for data, it is key to quantify and understand uncertainties in these data, as these insights can be used to design improved monitoring strategies. Such quantitative analysis has not yet been undertaken for visual riverbank litter sampling methods to date.
We conducted a series of experiments to quantify the measurement error of visual riverbank litter sampling. Our findings demonstrate that inter-observer variability can be substantial with a mean coefficient of variation of 22.4%. Statistical analysis indicates no significant effect of the assessed litter concentration, total item count, or sampling area size. In contrast, we did find that both size and colour significantly affect the item detectability by observers. Smaller items, especially those that are transparent or black, showed substantially lower recovery rates (below 50% for items <2.5 cm). Furthermore, we show that repeated observations of the same sampling area can significantly reduce uncertainty, with the largest improvement occurring with an increase from one to two observers (mean recovery rates increasing from 67.4% to 86.5%).
These findings reveal that measurement error is a key factor to be considered in visual riverbank litter sampling, especially for items smaller than 2.5 cm. Based on our results, we suggest two ways to reduce these uncertainties and improve reliability in monitoring protocols: 1) to observe the sampling area twice, and 2) to mitigate the lower recovery rates for smaller items through adding a step to the protocol with a more detailed measurement, or by correcting for the lower recovery rates during post processing. Incorporating these suggestions can contribute to reducing measurement error, improving long-term litter assessments and enhancing evidence-based decision-making in litter pollution management.
How to cite: Vriend, P., Vijver, M., van Loon, W., Collas, F., Drok, S., Kamp, N., and Bosker, T.: Reducing measurement error in riverbank litter sampling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5679, https://doi.org/10.5194/egusphere-egu26-5679, 2026.
Building on the methodological development carried out within the “Alplast” project, a newly developed isokinetic pump was successfully applied in combination with established net-based sampling methodology at several riverine measurement sites. This integrated approach allows for a comprehensive assessment of microplastic transport across a wide range of particle sizes, including the finest fractions that cannot be captured by net-based methods.
The combined application of net sampling and isokinetic pump sampling has proven to be robust and operational under varying field conditions form small streams to large rivers. While net sampling continues to effectively target coarser microplastic particles and enables the filtration of large water volumes, the isokinetic pump has delivered reliable results for the smallest size fractions. First experiences with laboratory analysis and data evaluation indicate that these fine particles represent a significant proportion of the total microplastic mass, hence they contribute substantially to overall microplastic transport, also due to their high mobility and widespread spatial distribution within the flow. The isokinetic sampling principle ensured that flow conditions at the intake were representative of the ambient river velocity, thereby minimizing sampling bias and enabling direct weighting of transport across the cross-section. This proved especially advantageous for capturing the variability in microplastic concentrations while keeping the number of required samples manageable.
Overall, the results confirm that the combination of net-based sampling and pump sampling with the isokinetic pump significantly enhances the representativeness of microplastic transport assessments in rivers. The methodology provides a sound basis for future studies aiming to quantify the role of fine microplastic fractions and contribute to standardized monitoring approaches.
How to cite: Liedermann, M., Mayerhofer, E., Krapesch, M., Gmeiner, P., and Pessenlehner, S.: Isokinetic pump sampling – first application results and contribution of smallest microplastic fractions to riverine transport, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19038, https://doi.org/10.5194/egusphere-egu26-19038, 2026.
The unchecked littering and mismanagement of plastics, coupled with their rising production and usage, have escalated them into one of the most pressing environmental pollutants. Among them, microplastics (<5 mm) and nanoplastics (<1 µm) have emerged as critical contaminants, with micro-and nanoplastics (MNPs) posing the greatest risks due to their ability to penetrate and contaminate water sources. While MPs are globally found to contaminate every freshwater ecosystem, it is reasonable to expect NPs to be similarly widespread as a result of MPs degradation with impacts still unknown. Importantly, land-based sources (wastewater systems) release MNPs into rivers ultimately contribute to the growing plastic pollution load in oceans, linking inland sources directly to marine contamination. Globally, numerous studies have examined the abundance, pathways, and removal efficiencies of MPs in wastewater treatment plants (WWTPs); however, systematic assessments of NPs remain scarce. Despite growing awareness of plastic pollution in European aquatic environments, size- and polymer-resolved data on MNPs in wastewater treatment systems and their subsequent release into receiving rivers remain scarce. To address this knowledge gap, the present study investigated the occurrence, size distribution, and polymer composition of MNPs across different treatment stages of a WWTP. Raw influent and treated effluent samples were collected from multiple treatment units and analysed using thermal desorption–proton transfer reaction–mass spectrometry (TD-PTR-MS). MNPs digestion and extraction followed a validated cascade filtration protocol employing membranes with pore sizes of 2700 nm (glass fibre), 1200 nm (silver), 200 nm (Anodisc), and 20 nm (Anodisc), enabling size-resolved characterization from the micro- to nanoscale. A diverse range of polymer types was detected, including polystyrene (PS), polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC), with tyre wear particles representing a notable non-conventional plastic fraction. To minimize potential contamination during field sampling and laboratory analyses, appropriate field, procedural, and system blanks were included. Significant variations in polymer composition and size classes were observed across treatment stages, allowing quantification of treatment-specific, size fraction, and polymer-specific MNPs removal efficiencies of the studied WWTP. This study provides a comprehensive dataset of MNPs accumulation within a European wastewater treatment system and their subsequent discharge into receiving aquatic environments.
How to cite: Parashar, N., Kolb, D., Heinle, J., and Materić, D.: Size- and Polymer-Specific Assessment of Micro- and Nanoplastics in a European Wastewater Treatment System, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8130, https://doi.org/10.5194/egusphere-egu26-8130, 2026.
Microplastics are plastic particles that are generally explained as being between 1μm and 5mm. They can be manufactured as micron-sized which are the primary microplastics, and can be formed by the breakdown of macroplastics, which are the secondary microplastics. Once in the marine environment, they are readily available for organisms to consume and accumulate. To date, they are identified from the water column, sediments, and marine biota. Despite the dramatic increase in microplastic studies observed in the last decades, their extraction and quantification from marine organisms remain hindered by several factors, including the lack of standardised protocols and technical limitations, especially for extracting microplastics smaller than 5 μm.
This work addresses key methodological gaps identified through a comprehensive review of existing studies that aimed to develop or optimise methods for microplastics extraction. We optimised key experimental parameters from existing extraction protocols to achieve complete digestion of the target tissue and efficient recovery of 1 µm microplastics, using Mytilus galloprovincialis as the model organism. Specifically, we refined the tissue-to-reagent ratio to ensure thorough digestion, followed by filtration and microplastic quantification using scanning electron microscopy. We also evaluated the addition of a catalyst during the chemical digestion phase, which improved digestion efficiency. Our results also highlight a tissue-specific digestion for the tested digestion agents. Preliminary results have shown promising recovery rates of microplastics. Its outcome will implement the plan outlined in the Marine Strategy Framework Directive 2008/56 by developing innovative solutions, such as enhanced analytical methods and technologies for detecting and measuring microplastics in biological tissues and the marine environment, to facilitate effective sea monitoring.
How to cite: Kurisingal Cleetus, M. C., Pontoni, L., Fabbricino, M., and Locascio, A.: Optimisation of Small Microplastic Extraction and Quantification from Marine Tissues, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1258, https://doi.org/10.5194/egusphere-egu26-1258, 2026.
The ever-increasing production of plastics, including single use items, has led to enormous amounts of pollution, threatening ecosystems, livelihoods, safety and human health. Rivers are important pathways for transporting plastic waste to the oceans.
Recent studies show that a substantial proportion of plastics is transported and retained below the water surface. Despite advances in monitoring technologies, current approaches focus mainly on counting or removing floating and deposited plastics, using visual counts, citizen science, drones, cameras, or GPS trackers. Leading to costly, labor-intensive, and environmentally invasive work.
Quantifying the full plastic transport behavior in the water column remains challenging, resulting in a lack of information on cross-sectional plastic flux. Our project aims to detect underwater riverine macroplastic pollution (>5 mm) using a multifrequency Acoustic Doppler Current Profiler (ADCP). While acoustic measurements show promise for plastic detection (Boon et al., 2023), a comprehensive understanding of how backscatter varies with item characteristics (size, shape, composition, and orientation) under different environmental conditions is still missing.
In this poster presentation, we will discuss the first results of using an echo sounder to detect plastics (PET, PP, PS) and other materials (e.g. paper, organic material and aluminum) in controlled and semi-controlled environments. We will present the first backscatter signatures from different polymer types and outline future approaches.
We anticipate that our results have the potential to provide continuous and cross-sectional estimates of underwater plastic transport in rivers. By providing insights into the impact of plastic pollution interventions and enabling accurate identification of underwater plastic behavior, this approach could support more effective mitigation and remediation efforts.
How to cite: Liese, N., van Emmerik, T. H. M., Waldschläger, K., Daugharty, M., Wallerstein, N., Vriend, P., Mani, T., Buschman, F., and Hoitink, T.: Understanding acoustic backscatters from underwater plastic items in controlled and semi-controlled environments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1748, https://doi.org/10.5194/egusphere-egu26-1748, 2026.
Plastic pollution is an emerging environmental challenge, threatening terrestrial, freshwater and marine ecosystems. Rivers are major pathways and storage systems, and large-scale plastic monitoring is necessary to effectively reduce plastic pollution. This presentation is about a study in which the detectability of plastics on riverbanks is investigated across spatial scales, ranging from in-situ hand-held spectrometers to large-scale satellites. We designed an experiment using two artificial plastic targets placed on the riverbanks of the Nederrijn, the Netherlands. The first target was a white polyester sheet of four different sizes (0.5x30 m2, 1x30 m2, 2x30 m2, 3x30 m2), and the second target consisted of transparent PET bottles with two different sizes and surface concentrations (3x30 m2 with 4 items/m2, 15x30 m2 with 8 items/m2). Data were collected with several sensors, covering a range of spatial, spectral, and temporal resolutions: the ASD Handheld 2 Spectroradiometer, the MAIA S2 multispectral camera, Sentinel-2, PlanetScope SuperDove, and EnMAP. We analyzed the reflectance spectra, developed a new index (SI-13), and applied a Naïve Bayes detection model to test the detectability of the plastic targets. Sentinel-2 images were successfully used to detect the three largest polyester targets. The PET targets were however not detected. In addition, we found high correlations (-0.93) between polyester target size and several spectral indices. Our results suggest that plastic detection satellite remote sensing is limited by both spatial resolution and plastic concentration. This paper serves as a proof of concept to show that plastic detection in riverbank environments using satellite and camera imagery is feasible and should be investigated further.
How to cite: Maathuis, M., Rußwurm, M., Bochow, M., and van Emmerik, T.: Exploring plastic detectability on riverbanks using remote sensing, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1899, https://doi.org/10.5194/egusphere-egu26-1899, 2026.
Plastic pollution monitoring remains challenging in complex and dynamic environments such as coastal landfills. These anthroposystems contain multiple plastic sources, transport pathways, and fragmentation processes that coexist and interact. Due to their proximity to the shoreline and their vulnerability to erosion, they represent a significant potential source of plastics and microplastics (MPs) into the environment. However, this environmental compartment is often overlooked and understudied in terms of its role in releasing plastics and MPs. While substantial research focuses on plastic transport and presence in marine environments, few studies consider nearshore landfills as a source of plastics and MPs. Moreover, the similarities between sediment and plastic transport processes have been little investigated. The same applies to the relationship between coastal cliff erosion and the fragmentation of plastics into MPs.
This study proposes a multi-scale analytical approach combined with field-based observations. To this end, macroplastic exports were monitored using an adapted OSPAR protocol, which enabled the identification, quantification, and temporal tracking of plastic debris from coastal landfills and other sources. MP contamination in sediments was investigated using a combined approach of micro-Fourier Transform Infrared Spectroscopy (µ-FTIR) and the thermal Rock-Eval® method. The integration of these methods allows for precise polymer identification and abundance measurement via µ-FTIR, alongside mass-based quantification with the Rock-Eval® device. Those approaches were applied to two contrasting coastal landfill sites: Dollemard (Normandy, France) and Sant’Agata (Calabria, Italy).
Results from macroplastic monitoring highlight spatial variations in the origins of macroplastics around both coastal landfill sites. Along transects located in the direct axis of the landfills, landfill discharge represents, on average, ~65% of the collected items, confirming these sites as active local sources of plastic pollution. In contrast, transects outside the landfill axis display highly variable compositions. At the Dollemard site, for transects downstream of the longshore drift, ~75% of plastics are attributed to beached marine litter. Additionally, across all transects, approximately 25% of the collected plastics consist of highly fragmented debris whose precise origin is difficult to determine. Furthermore, temporal variations in plastic abundance and origin were observed across all transects, reflecting the influence of storm events and short-term remobilization processes. Field observations also highlight the role of cliff erosion, gravity-driven processes, and sediment remobilization in controlling the release, transport, and fragmentation of plastics from macro- to MPs. Sediment analysis reveals high levels of plastic impregnation in both coastal landfill deposits, with MP abundances reaching up to 24,816 MPs/kg for Dollemard and 110,970 MPs/kg for Sant’Agatha. Estimations of mass-concentrations were also made using µ-FTIR and compared with Rock Eval® analysis results. These comparisons show a significant disparity in results depending on the MP abundance and nature of each sample.
Consequently, this study tries to demonstrate that coastal landfills should be considered key monitoring targets for plastic pollution across the geosphere. With the multi-scale proposed approaches, long-term monitoring strategies could be implemented to better understand plastic fluxes from coastal landfills and from other sources.
How to cite: Lieunard, V., Bailleul, J., Rohais, S., Romero Sarmiento, M.-F., Roussel, H., and Rabaud, B.: Coastal landfills as sources of plastic and microplastic pollution: a multi-scale monitoring approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3849, https://doi.org/10.5194/egusphere-egu26-3849, 2026.
Studies reporting environmental MP concentration rarely cover the full MP size range of 1 to 5000 µm due to sampling and analytical limitations. However, microplastic (MP) number concentration in the environment increases exponentially with decreasing particle size. This leads to difficulties in the intercomparison of studies, which is critical for environmental and human health risk assessment. Indeed, for the same MP sample, a study observing the small MP fraction (1-300 µm for ex.) will report a higher number concentration than another study observing the large MP fraction (300-5000 µm) of the same sample.
In this presentation, we summarize the current understanding of the MP particle size distribution (PSD), based on the power law model (Segur et al., 2025). We confront the power law model with 90 published MP PSD observations from the literature, compiled in the new MPsizeBase open access database (Sonke et al., 2025). We show that the MP PSD power law slope is influenced by particle shape (fragments, fibers), but does not vary significantly between environmental compartment studied (surface ocean, deep ocean and atmosphere).
We propose simple equations to extrapolate MP concentrations for the limited observed size range to the full MP size range (1 to 5000 µm), or any other sub-size range, for both MP number and mass concentrations. By comparting the observed MP concentrations to the corrected full size range MP concentration, we show that the 90 published studies underestimated MP number concentrations.
The MP number PSD is dominated by small fragments: in the surface ocean, we estimate that 70% of MP particles have a diameter between 1 and 2 µm. Conversely, we also show that the MP mass PSD is dominated by large particles and estimate that, for surface ocean MP, common plankton nets (mesh size 300 - 330 µm) only catch 0.003% of all MP particles (in number), but 94% of MP mass. This indicates the need to express results both in term of numeric and mass concentration. To do so, we provide simple equations to convert a numeric PSD to mass PSD.
References
Segur, T., Hough, I., Dobiasova, N., Voisin, D., Richon, C., Angot, H., Thomas, J. L., and Sonke, J. E.: Using the power law size distribution to extrapolate and compare microplastic number and mass concentrations in environmental media, Research Square preprint, https://www.researchsquare.com/article/rs-8524083/v1, 2025.
Sonke, J. E., Segur, T., Hough, I., Dobiasova, N., Voisin, D., Yakovenko, N., Margenat, H., Hagelskjaer, O., Abbasi, S., Bucci, S., Richon, C., Angot, H., Thomas, J. L., and Le Roux, G.: MPsizeBase: a database for particle size distributed environmental microplastic data, EarthArXiv, preprint, https://eartharxiv.org/repository/view/10605/, 2025.
How to cite: Sonke, J., Segur, T., Hough, I., Dobiasova, N., Voisin, D., Richon, C., Thomas, J., and Angot, H.: Comparing apples and oranges: Using the MPsizeBase and power law size distribution to extrapolate and inter-compare microplastic concentrations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7641, https://doi.org/10.5194/egusphere-egu26-7641, 2026.
Microplastics (MPs) are widely recognized as emerging contaminants that threaten aquatic ecosystems and human health. Stormwater runoff serves as a major transport pathway, mobilizing MPs accumulated on urban surfaces into receiving waters; however, quantitative information on rainfall-driven MP mobilization remains limited.
This study quantified the emission characteristics and loads of MPs discharged during a 14-mm rainfall event at Samhocheon, a coastal urban creek connected to Masan Bay, South Korea.
Time-weighted stormwater sampling was conducted, and mass-based MP concentrations were determined using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) following organic matter removal and density separation. The baseline MP concentration prior to rainfall was 6.13 μg/L. Concentrations increased sharply during the initial runoff phase, peaking approximately 1.5 hours after runoff onset, and gradually declined with decreasing rainfall intensity. The event mean concentration (EMC) was 11.93 μg/L. Polypropylene, polyethylene, and polyvinyl chloride were the dominant polymers, accounting for 60–80% of MPs.
Tire wear particles (TWPs), quantified using styrene–butadiene rubber as a proxy, contributed 20–68% of the total MP load. The total MP (>20 μm) load discharged to Masan Bay during the event was 100.3 g based on Py-GC/MS data, with 84% (84.5 g) mobilized during the first 20% of the runoff duration. This estimate was comparable to the FTIR-based load (62.32 g) calculated from particle dimensions.
Overall, the findings demonstrate the utility of Py-GC/MS as a complementary technique to FTIR for MP monitoring and highlight early-stage stormwater runoff as a critical period for MP mobilization. These results emphasize the need for targeted urban watershed management strategies to reduce MP emissions to aquatic environments.
How to cite: Ha, S. Y., Cho, Y., Han, G. M., and Hong, S. H.: Quantifying Microplastic Loads from Urban Stormwater Runoff Using Pyrolysis-GC/MS: Insights from a Coastal Creek in South Korea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8471, https://doi.org/10.5194/egusphere-egu26-8471, 2026.
Coastal plastic pollution monitoring efforts are frequently focused on riverine and offshore inputs and production. While these inputs are the majority of plastics to the coastal environment in many regions, Mediterranean regions with limited precipitation and relatively small, undisturbed watersheds may have limited fluvial inputs of plastics. However, the beaches of these regions are heavily utilized by the tourism industry, and littering due to beach visitation is an understudied, but potentially significant source of plastic pollution.
In this study, we document a citizen-science led effort to quantify tourism-derived litter production on a pocket beach in a Mediterranean environment, Laguna Beach, California. This study trained community volunteers consisting of concerned citizens + local high school students in litter sampling and categorization. Field surveys from the summer of 2025 found over 1,300 items of trash, including 700 plastics, on a 100x20 meter pocket beach. We then tested the effectiveness of enhanced signage as an policy intervention for reducing tourism derived litter. Statistical analysis found no difference between trash loading pre vs post enhanced signage.
Further analysis of the data found that a significant amount of trash production occurred during just a few holiday weekends. Future work will test a range of policy interventions from enhanced ranger patrols, to offering free parking to visitors who collect trash.
How to cite: Brand, M., Weirich, M., Rothman, H., and Harwood, G.: Quantifying Tourism-Derived Litter Accumulation on a Southern California Pocket Beach Using Citizen Science, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15138, https://doi.org/10.5194/egusphere-egu26-15138, 2026.
Monitoring floating plastic transport in rivers is essential for quantifying plastic flux and guiding pollution mitigation strategies. While traditional approaches relied on manual collection or visual observation, recent advancements have increasingly adopted image-based methods that integrate deep learning with remote sensing technologies, including satellite imagery, UAVs, and fixed-point cameras. Although visual observation remains widely used for global-scale assessment, it is constrained by high labor demands, observer subjectivity, and safety risks during flood events.
To address these limitations, Kataoka et al. (2025) developed RiSIM (River Surface Image Monitoring software), which utilizes fixed river cameras and deep learning models for plastic detection, classification, and object tracking for floating debris. RiSIM demonstrated high reliability in Japanese river systems (r = 0.91 for quantity; r = 0.80 for mass). However, its performance has so far been evaluated exclusively within Japan.
As described in Kataoka et al. (2025), a cloud-based monitoring platform, PRIMOS, has been released to facilitate the application of RiSIM. Operating through a standard web browser with server-side computation, PRIMOS eliminates technical barriers such as local environment setup and high-performance hardware requirements. By integrating the fine-tuning capabilities examined in this study, the platform aims to support researchers and monitoring projects in conducting plastic transport analyses across diverse river systems worldwide.
This study evaluates the global applicability of RiSIM using nadir-view video data collected from Saluran Cideng (a tributary of Kali Cideng) in Jakarta, Indonesia—a first step toward assessing its transferability to Southeast Asian rivers. Using the PRIMOS platform, we evaluate the detection performance of the AI model integrated into RiSIM at Saluran Cideng. Furthermore, we examine methodology for fine-tuning and retraining to enhance the system's applicability to the local environment. The broader applicability of the framework and practical considerations for deployment will be discussed.
The monitoring data for this RiSIM evaluation was collected under the “Project on Inventory Development Methodology for a Plastic Leakage into the Environment, Including the Marine Environment”, commissioned by the Ministry of the Environment, Japan.
How to cite: Sasaki, K., Kataoka, T., Cordova, M. R., Aoki, D., and Tetsusaki, S.: Evaluating the Applicability of RiSIM for AI-Based River Plastic Monitoring to an urban river in Indonesia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16067, https://doi.org/10.5194/egusphere-egu26-16067, 2026.
The increasing use of bioplastics in food packaging and consumer goods requires a clear understanding of their fate within real waste management systems in order to avoid environmental pollution. This study investigated the composting process of digestates obtained from the anaerobic digestion (AD) of polylactic acid (PLA) and poly(butylene 2,5-furanoate) (PBF) co-treated with the organic fraction of municipal solid waste (OFMSW), focusing on polymer transformation, compost quality, and environmental implications. After mesophilic AD, the residual digestates containing degraded PLA and nearly intact PBF fragments were subjected to controlled aerobic composting for 90 days under simulated full-scale conditions. Temperature and aeration were monitored to ensure the proper succession of mesophilic, thermophilic, cooling, and maturation phases. The resulting composts were characterized for physicochemical parameters, including C/N ratio, total organic C, total Kjeldahl N, NH4+-N, water-extractable organic C (WEOC), and water-extractable N (WEN), while residual polymer fragments were examined using FTIR-ATR spectroscopy and optical microscopy. Germination tests were performed to assess phytotoxicity and agronomic suitability. Results showed that the sequential AD-composting process ensured complete mineralization of PLA, with no detectable residues already at the end of the AD stage. The compost derived from PLA-containing digestate exhibited stable organic matter, showing a C/N ratio of about 22, a WEOC/WEN ratio around 10, and low NH4+-N. Conversely, PBF displayed strong recalcitrance, persisting as visible fragments even after composting. FTIR-ATR analysis revealed only minor surface modifications, suggesting that aerobic treatment did not significantly alter the polymer's molecular structure. Nevertheless, the compost obtained from the PBF-containing digestate showed good stabilization, displaying a C/N ratio of approximately 21, a WEOC/WEN ratio of about 10, along with limited NH4+-N content. Germination assays revealed noticeable phytotoxicity at compost concentrations above 25%, whereas at 25% dilution the germination index reached 73% and 57% for the PLA- and PBF-derived composts, respectively. These results indicate that composts from PLA-containing digestates may be suitable for agricultural application after adequate dilution or blending with mature compost, whereas those derived from PBF require careful management due to the persistence of undegraded residues. From a sustainability perspective, the integrated AD-composting approach supports energy recovery from OFMSW while generating partially stabilized composts. However, the resistance of PBF to both anaerobic and aerobic degradation highlights the need for polymer redesign or tailored end-of-life strategies to prevent long-term environmental accumulation. Overall, this study underscores the value of combining physicochemical and agronomic evaluations to accurately assess the biodegradability and environmental fate of emerging bioplastics within circular organic waste management systems.
This work has been funded by the European Union – NextGenerationEU under the Italian Ministry of University and Research (MUR) National Innovation Ecosystem grant ECS00000041 - VITALITY - CUP J97G22000170005.
How to cite: Montegiove, N., Lotti, N., Puglia, D., Pellegrino, R. M., and Pezzolla, D.: Composting of anaerobically treated bioplastic-containing organic waste: behavior of polylactic acid (PLA) and poly(butylene 2,5-furanoate) (PBF) and quality of final compost, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16904, https://doi.org/10.5194/egusphere-egu26-16904, 2026.
Nanoplastics (NPs) are an emerging class of pollutants that remain challenging to accurately quantify in environmental matrices. Increasing evidence suggests their potential for long-range atmospheric and aquatic transport, contributing to their global distribution [1,2]. Understanding NP occurrence in remote environments is therefore essential for identifying sources, transport pathways, and baseline background levels.
In this study, we analyzed water samples from Loch Ness and surrounding rivers and channels in the Scottish Highlands to assess the presence and composition of nanoplastics using Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry (TD-PTR-MS) [3]. This represents one of the first reports of nanoplastics in UK inland waters.
The dominant polymer types detected were polyethylene terephthalate (PET), polyethylene (PE), and tire-wear particles (TWP). Nanoplastics were present even at depths exceeding 100 m in Loch Ness. Subsurface NP concentrations in lakes were influenced by the proximity of local sources, while among the rivers, the Ness River showed the highest levels near urban areas, with some tributaries exhibiting no detectable NPs.
Spatial patterns suggest a mix of local and long-range inputs. Elevated NP concentrations near populated and industrial areas point to local emissions, while consistent background levels of PET across remote sites indicate atmospheric or diffuse sources. These findings demonstrate nanoplastics to be pervasive even in isolated freshwater systems, and underline the need for integrated monitoring approaches to better understand their transport and fate.
References
[1] D. Materić, M. Peacock, J. Dean, M. Futter, T. Maximov, F. Moldan, T. Röckmann, R. Holzinger, Presence of nanoplastics in rural and remote surface waters, Environ. Res. Lett. 17 (2022) 054036. https://doi.org/10.1088/1748-9326/ac68f7.
[2] D. Allen, S. Allen, S. Abbasi, A. Baker, M. Bergmann, J. Brahney, T. Butler, R.A. Duce, S. Eckhardt, N. Evangeliou, T. Jickells, M. Kanakidou, P. Kershaw, P. Laj, J. Levermore, D. Li, P. Liss, K. Liu, N. Mahowald, P. Masque, D. Materić, A.G. Mayes, P. McGinnity, I. Osvath, K.A. Prather, J.M. Prospero, L.E. Revell, S.G. Sander, W.J. Shim, J. Slade, A. Stein, O. Tarasova, S. Wright, Microplastics and nanoplastics in the marine-atmosphere environment, Nat. Rev. Earth Environ. (2022) 1–13. https://doi.org/10.1038/s43017-022-00292-x.
[3] D. Materić, A. Kasper-Giebl, D. Kau, M. Anten, M. Greilinger, E. Ludewig, E. van Sebille, T. Röckmann, R. Holzinger, Micro- and Nanoplastics in Alpine Snow: A New Method for Chemical Identification and (Semi)Quantification in the Nanogram Range, Environ. Sci. Technol. 54 (2020) 2353–2359. https://doi.org/10.1021/acs.est.9b07540.
How to cite: Materić, D., Peacock, M., and Gibb, S.: Nanoplastics in Loch Ness and surrounding rivers and channels, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17738, https://doi.org/10.5194/egusphere-egu26-17738, 2026.
Rivers are key pathways for transporting plastic pollution to the ocean, yet global estimates of riverine plastic export remain highly uncertain due to catchment diversity and the complexity of transport processes. To better understand dynamics at the river–ocean interface, we analyzed a comparative dataset from three rivers in the Caribbean, Southern Africa, and Southeast Asia, each characterized by distinct hydrometeorological and tidal regimes. We tracked 196 GPS drifters and monitored surface transport using forty-one cameras deployed across six river locations over multiple seasons. These observations informed simulations of three years of plastic transport (2020–2022). We find that rivers flush 50% of their floating plastics downstream within only 7–12% of the time. Annual average mass fluxes for the three rivers were 34–98% lower than previously reported by global models. Our results highlight that rivers act as long-term sinks for plastic pollution, and that estuarine transport is more limited than often assumed. This study provides critical observational and modelling insights to refine river‑to‑ocean plastic flux estimates and emphasizes the heterogeneity of emission dynamics across diverse river systems.
How to cite: Mani, T., Ebner, R., Pinson, S., Piemjaiswang, R., Murray, A. M., Svensson, M., van Emmerik, T. H. M., Chavanich, S., Trois, C., Sanlley, C., and Lebreton, L.: How Rivers Export Plastic: Insights from Three Contrasting Global Systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22963, https://doi.org/10.5194/egusphere-egu26-22963, 2026.
