OS4.5 | Monitoring, Modeling and Risk Mapping of Marine Pollution and its Environmental and Socioeconomic Footprints
EDI
Monitoring, Modeling and Risk Mapping of Marine Pollution and its Environmental and Socioeconomic Footprints
Convener: Svitlana Liubartseva | Co-conveners: George Zodiatis, Sebastien Legrand, Luisa Galgani, Panagiota Keramea
Orals
| Fri, 02 May, 10:45–12:25 (CEST)
 
Room L2
Posters on site
| Attendance Fri, 02 May, 14:00–15:45 (CEST) | Display Fri, 02 May, 14:00–18:00
 
Hall X4
Orals |
Fri, 10:45
Posters on site
Fri, 14:00
To investigate the routes and endpoints of marine contaminants such as anthropogenic hydrocarbons, heavy metals, marine litter, including plastics and e-waste, HNS, POPs, radionuclides, PFAS, pharmaceutics, etc., oceanographic monitoring and models are widely applied. This session covers monitoring strategies, lab studies, computational tools, and web-based applications to track marine pollutants and their effects at the local, regional, and global levels. Advanced observational techniques, protocols, and toxicity testing; ensemble and multi-model simulations; machine learning and artificial intelligence applications are among the subjects that are being solicited.

Studies linking effects to broader ecosystem stressors, such as climate change and environmental degradation, are particularly welcome. Increased anthropogenic pressure in the Arctic Ocean resulting from the melting of polar ice makes researching marine pollutant transfer under ice conditions extremely valuable.

The session's key questions are: What do we know about sources of marine pollution? Which factors affect the dispersion of pollutants in the marine environment? What happens to the contaminants in the water column, sediments, and on the sea surface? How do marine pollutants interact with marine ecosystems?

The impact of other environmental stressors such as artificial light, noise, and thermal pollution on marine ecosystem resilience is also a significant topic for discussion.

Orals: Fri, 2 May, 10:45–12:30 | Room L2

Chairpersons: Svitlana Liubartseva, George Zodiatis, Sebastien Legrand
10:45–10:55
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EGU25-370
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ECS
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On-site presentation
Impact of ocean dynamics on microplastics distribution in two oceanic eddies 
Álvaro Cubas, Ana Molina-Rodríguez, Francisco Machín, Eugenio Fraile-Nuez, and Daura Vega-Moreno

Plastic pollution has become a significant issue in marine ecosystems, with microplastics posing unique challenges due to their size and widespread dispersal. These particles tend to get accumulated in oceanic structures like eddies, which often act as attractors, where microplastic distribution is shaped by complex circulation patterns. We study the distribution and concentration of microplastics within two distinct oceanic eddies downstream of the Canary Islands, an anticyclonic and a cyclonic eddy sampled during two recent oceanographic campaigns in 2021 and 2022 respectively. We focused on characterizing the spatial distribution of microplastic particles, specifically distinguishing between fragments and fibers, to understand their prevalence and variability within each eddy. By analyzing these patterns, we aim to elucidate the physical processes that may govern the accumulation and dispersal of microplastics in these mesoscale structures.

To contextualize our observations, we utilized trajectory data from an eddy trajectory atlas to track the development and movement of each eddy over time. This enabled us to map the eddies’ lifecycles and physical characteristics, such as amplitude, effective radius, and shape, which may influence microplastic transport and retention. Through this combined approach, we explore how each eddy’s unique dynamics affects vertical microplastic distribution.

Preliminary findings suggest that microplastic fibers and fragments exhibit distinct spatial distributions within cyclonic versus anticyclonic eddies, influenced by differential dynamics. Our results provide awareness into the role of mesoscale oceanographic features in shaping microplastic distribution and transport.

How to cite: Cubas, Á., Molina-Rodríguez, A., Machín, F., Fraile-Nuez, E., and Vega-Moreno, D.: Impact of ocean dynamics on microplastics distribution in two oceanic eddies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-370, https://doi.org/10.5194/egusphere-egu25-370, 2025.

10:55–11:05
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EGU25-61
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On-site presentation
Mercury levels in Loggerhead and Green Sea turtle eggshells from nests along the southeastern Mediterranean coast 
Jacob Silverman, Orin Levin, Yaniv Levy, Olga Rybak, and Mustafa Asfur

Sea turtles roam vast regions of the Mediterranean Sea throughout their lives, during which they accumulate mercury, primarily as a function of their tropic level and age. This study examined the spatial distribution of mercury in hatched eggshells of loggerhead sea turtles (caretta caretta, n=200) and green sea turtles (chelonia mydas, n=40) from nests along the Mediterranean coast of Israel. This was done to determine spatial trends of mercury exposure on a regional scale in nesting females, assuming that eggshell mercury levels are related to the mother’s mercury burden. Ten eggshells were sampled from each nest during the nesting seasons of 2022, and 2023 (n=22).

Some of the nests were transferred to protected enclosures after the eggs were laid. In general, mean mercury levels in each nest varied greatly between nests from the same enclosures and between different shores in both species. As expected, the mean mercury level in loggerhead eggshells was significantly higher than green sea turtle eggshells (8±1 and 1.0±0.5 ppb (mean±SE), respectively, p<0.0001). Furthermore, mercury in loggerhead eggshells decreased from the northern to the southern region of Israel from 10±1 ppb (n=100) to 5.4±0.3 ppb (n=80), respectively. Finally, mercury levels in loggerhead eggshells are substantially higher and more robust (much higher sample size of eggs and nests in this study) than previously reported values from other regions in the Mediterranean Sea and globally. This result suggests that eastern Levantine sea-turtles are more exposed to mercury pollution than other marine areas of the Mediterranean Sea and globally. 

How to cite: Silverman, J., Levin, O., Levy, Y., Rybak, O., and Asfur, M.: Mercury levels in Loggerhead and Green Sea turtle eggshells from nests along the southeastern Mediterranean coast, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-61, https://doi.org/10.5194/egusphere-egu25-61, 2025.

11:05–11:15
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EGU25-1615
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On-site presentation
A laboratory assessment of the influence of wind and sea currents on the dispersion of pellets from the Toconao incident 
Paula Núñez, Ana J. Abascal, Irene Ruiz, Anna Rubio, and Andrés García

On December 8, 2023, the cargo ship Toconao was involved in a maritime incident off the coast of northern Portugal that resulted in the loss of 1,000 bags of buoyant plastic pellets, or nurdles. The pellets fell into the sea and reached the Bay of Biscay, posing a potential threat to the coasts of Spain and France. In the weeks following the incident, pellets were found washing up on beaches throughout northern Spain, particularly in Galicia, Asturias, Cantabria and the Basque Country. In response to this environmental emergency, several contingency plans were activated along the Spanish coast, requiring the use of scientific tools such as numerical modeling to develop effective responses. Nevertheless, a lack of detailed knowledge of the factors governing the transport and dispersion of these pellets made accurate predictions difficult, posing a significant challenge to effective management and mitigation of the spill.


For this reason, a set of laboratory experiments was conducted to study the dispersion of pellets under a range of hydrodynamic and wind conditions in two different physical settings. The behavior of the pellets collected from the Toconao spill, which showed a density of 900 kg/m³, was assessed in two different sections of a hydraulic flume (Z1 and Z2 zones) under different combinations of water level, current, and wind. Zone Z1, located within the flume itself (2 m x 0.35 m), exhibits a unidirectional flow pattern. In contrast, zone Z2, located in the expanded section of the flume (3 m x 1.5 m), shows three-dimensional asymmetric flow patterns. Hydrodynamic conditions were defined by combining one water level in each zone (30 and 40 cm in Z1 and Z2, respectively) and three flow rates (30, 40 and 50 l/s in both zones). In addition, the effect of four wind conditions was tested for the average flow rate of 40 l/s (in Z1: no wind, 0.5, 1.0, and 1.5 m/s; in Z2: no wind, 0.3, 0.7, and 1.1 m/s). The results provide valuable information on the effects of wind and ocean currents on the dispersion of a group of plastic pellets and demonstrate the importance of surface currents in this process. In addition, these findings provide a comprehensive database for validating numerical transport models, which will improve their predictive ability and usefulness in future emergencies.

How to cite: Núñez, P., Abascal, A. J., Ruiz, I., Rubio, A., and García, A.: A laboratory assessment of the influence of wind and sea currents on the dispersion of pellets from the Toconao incident, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1615, https://doi.org/10.5194/egusphere-egu25-1615, 2025.

11:15–11:25
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EGU25-11395
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On-site presentation
Simulation of anthropogenic tritium discharge into the ocean from the Fukushima Daiichi Nuclear Power Plant 
Alexandre Cauquoin, Maksym Gusyev, Yoshiki Komuro, Jun Ono, and Kei Yoshimura

Following the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011, large quantities of radioactive materials were released into the atmosphere and ocean. Since the FDNPP nuclear accident, Tokyo Electric Power Company (TEPCO) operators have been implementing measures to reduce groundwater inflow into the FDNPP damaged reactor buildings while pumping water to cool the nuclear reactors and fuel debris. The resulting huge water volume began the discharge into the ocean from August 2023, after being treated by an Advanced Liquid Processing System (ALPS) to remove radionuclides for acceptable discharge levels except tritium. Since then, tritium concentrations in seawater and aquatic ecosystems near the FDNPP site are continuously monitored and disseminated publicly. It is essential to assess the long-term safety threshold of ALPS-treated water discharge procedure in terms of tritium concentration in coastal areas of Japan and the Pacific Ocean. However, there is no global oceanic simulation with tritium concentration and, by extension, no projection of tritium concentration at Pacific Ocean scale.

In this study, we used the TEPCO ALPS treated water release plan as an input to the ocean general circulation model (OGCM) COCO4.9, which is the ocean component of the Model for Interdisciplinary Research on Climate, version 6 (MIROC6 [1]). This approach allowed us to simulate the anthropogenic tritium concentration in the ocean due to ALPS treated water release in the forthcoming decades. The spatial distribution and temporal evolution of the projected tritium concentrations in different parts of the Pacific Ocean, as well as the impact of global warming on them, were analyzed. Moreover, the anthropogenic tritium concentration following the FDNPP accident was modeled to evaluate how large the tritium concentrations due to current treated water release are compared to the accidental one in 2011. Finally, given that oceanic tritium concentrations are mainly controlled by ocean mixing, our study represents a valuable opportunity to evaluate the impact of the Kuroshio current representation in COCO4.9 on tritium concentrations at non-eddy-resolving and eddy-resolving horizontal resolutions.

[1] Tatebe et al., Geosci. Model Dev., 12, 2727–2765, doi:10.5194/gmd-12-2727-2019, 2019.

How to cite: Cauquoin, A., Gusyev, M., Komuro, Y., Ono, J., and Yoshimura, K.: Simulation of anthropogenic tritium discharge into the ocean from the Fukushima Daiichi Nuclear Power Plant, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11395, https://doi.org/10.5194/egusphere-egu25-11395, 2025.

11:25–11:35
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EGU25-15766
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On-site presentation
Model based analysis of fate of contaminants of emerging concern in the water column and the sediment of the Oslofjord 
Evgeniy Yakushev, Malcolm Reid, Maria Austrheim, Samantha Martins, and Steven Brooks

6 contaminants of emerging concern (CEC): clarithromycin, citalopram, tributyl phosphate, benzotriazole, octocrylene and teflubenzuron, with  differing sources, applications, and contrasting properties were selected for modeling in the water column and the sediments of the Oslofjord. The FABM family of models was used, which coupled benthic-pelagic model 2DBP together with the biogeochemical model BROM and the elaborated contaminants transformation module. This parameterized processes of CEC partitioning with organic matter, and CEC decay due to biodegradation, photolysis and hydrolysis. This combination of modules allows for the simulation of spatial and temporal variability of CEC during a period of intensive pollution and restoration. It was shown that (i) the biological pump significantly affects transformations of CECs leading to seasonal variation of concentration in the water column, (ii) During the pollution period fluxes of particulate and dissolved matter are directed to the sediments, while there is a flux of dissolved CEC from the sediments, (iii) After cessation of the pollution there can be predicted flux of dissolved CEC from the sediments for a certain period, (iv) Properties of the CEC determine the effectiveness of the biological pump and duration of CEC existence in the water column and the sediments following the cessation of pollution. This work was supported by Grant Agreement 101135037 – CONTRAST – Horizon CL6-2023.

How to cite: Yakushev, E., Reid, M., Austrheim, M., Martins, S., and Brooks, S.: Model based analysis of fate of contaminants of emerging concern in the water column and the sediment of the Oslofjord, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15766, https://doi.org/10.5194/egusphere-egu25-15766, 2025.

11:35–11:45
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EGU25-8802
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ECS
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On-site presentation
Perfluorooctanoate and nano-titanium dioxide modulate male gonadal function in the mussel Mytilus coruscus  
Bingyan Sun, Christian Bock, and Youji Wang

Perfluorooctanoic acid (PFOA) and nano-titanium dioxide (nano-TiO₂) are widely used in industrial applications such as manufacturing and textiles, and can be released into the environment, causing toxicity to marine organisms. To study the effects of these pollutants on the gonadal development, we exposed the males of Mytilus coruscus to varying PFOA concentrations (2 and 200 μg/L) alone or combined with nano-TiO2 (0.1 mg/L, size: 25 nm) for 14 days. Co-exposure to PFOA and nano-TiO₂ resulted in a short-term (7 days) decrease in the gonadosomatic index (GSI), which recovered to baseline levels. In contrast, long-term (14 days) exposure induced changes in the testes, including increased protein content, decreased lipid content, reductions in spermatic area and sperm count, and elevated apoptotic cell levels. Furthermore, key genes essential for gonadal maturation were significantly upregulated after long-term exposure. PFOA and nano-TiO2 can disrupt the gonadal function in the male mussels by interfering with Wnt family signaling pathways, modulation of steroid and lipid metabolism and induction of apoptosis. Therefore, PFOA and nanoparticle pollutants may pose a significant risk to the reproductive capacity of mussels’ populations from polluted coastal environments.

How to cite: Sun, B., Bock, C., and Wang, Y.: Perfluorooctanoate and nano-titanium dioxide modulate male gonadal function in the mussel Mytilus coruscus , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8802, https://doi.org/10.5194/egusphere-egu25-8802, 2025.

11:45–11:55
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EGU25-17018
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ECS
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On-site presentation
Assessing Oil Spill Hazard Along the Aegean Sea Coastline 
Asimakis-Nestoras Karagiannis, Antonio Olita, Dimitra Kitsiou, and Theodoros Nitis

Oil spills represent a significant environmental hazard, particularly in regions with high maritime activity and vulnerable coastlines. 

This study aims to assess oil spill hazard along the Aegean Sea’s coastline by simulating continuous oil spill scenarios over 1 year (2021) using the GNOME model developed by NOAA. The simulation focused on the Aegean's area of highest tanker vessel density, extrapolated from vessel traffic data. We located a main “corridor” that was supposedly the area where an accident and/or a systematic release of oil at sea is more likely to happen. Within the extent of this area, we drew a grid with 69 points of continuous release, spaced each other 5 – 10 km away each releasing 80 particles per hour and 1 ton of oil daily.

The oil spill model was forced with ERA5 (ECMWF Reanalysis) to address atmospheric parameters, with a spatial resolution of 31 km^2 and a temporal one of 1 hour. Surface currents were provided by MFS ocean model with a spatial resolution of 4 km^2 and a temporal of 1 hour (provided by Copernicus portal) t. Daily remotely sensed L4 SST data from Copernicus were also used to account for evaporation. Waves were parameterized from wind data, as they are required for emulsification and dispersion processes.

Results showed that all year round most particles tend to be beached between the 3rd and 10th day since release, peaking at day 5. The same for mass, and with no evident seasonality. Seasonal variations were observed regarding few particles that were afloat for longer times, with particles during the summer showing a lower maximum age at beaching, peaking at day 20. The latter could be attributed to increased wind speeds typical of the Aegean Sea summer period, which can prolong particle transport. 

The total density analysis of the whole simulation highlighted that the central Aegean region exhibited the highest pollution values, while lower values were observed in the northern Aegean with some southern islands also displaying areas of higher density.

How to cite: Karagiannis, A.-N., Olita, A., Kitsiou, D., and Nitis, T.: Assessing Oil Spill Hazard Along the Aegean Sea Coastline, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17018, https://doi.org/10.5194/egusphere-egu25-17018, 2025.

11:55–12:05
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EGU25-20024
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On-site presentation
Investigating River-Marine Interactions and Plastic Pollution Dynamics Using a Multimodel Approach to Support Policy Development in Environmentally Sensitive Areas 
Carlo Brandini, Rossella Mocali, Michele Sacco, Michele Bendoni, Bartolomeo Doronzo, Elisabetta Tomei, Francesco Manetti, Stefano Taddei, Massimo Perna, and Luca Solari

The majority of marine plastic pollution originates from land-based sources that reach the sea via rivers (Jambeck et al., 2015; Lebreton et al., 2017). In dispersion models, this process is often oversimplified as a single-point discharge at the river mouth. However, the input of macroplastics into the sea and subsequent dispersion or deposition processes —strongly influenced by the characteristics of the plastics— are significantly affected by small-scale phenomena. In coastal areas, wave-induced hydrodynamics, wind, and the complex interactions between marine currents and river inflow play a predominant role (Guo et al., 2020). These complexities are not adequately represented in Lagrangian circulation and dispersion models typically applied at the coastal, shelf and basin scale.

In this study, we focus on integrating observational data, acquired through drone surveys of stranded plastics on beaches, and simulation data obtained via a multimodel approach. This approach incorporates both phase-averaged and phase-resolving wave models. The latter are particularly suitable for small-scale processes (e.g., at the river mouth) to describe dispersion and stranding dynamics.

Our pilot study area is the mouth of the Arno River, located within the San Rossore Natural Park, an environmentally valuable area where macroplastic pollution is notably evident, as highlighted by numerous surveys (e.g. Merlino et al., 2020). The observed patterns are replicable using the hydrodynamic dispersion models employed. Observational data were collected using drone flights at various altitudes with differing levels of detail, some of which were processed through machine learning algorithms (Liu et al., 2021).

Dispersion and deposition processes at the river-mouth scale, analyzed using these two modeling approaches, reveal distinct advantages. Large-scale coastal deposition processes (spanning kilometers) are better described using the phase-averaged approach, while small-scale fluvio-marine interactions (hundreds of meters) and stranding processes are more accurately captured by the phase-resolving approach. Furthermore, this dual approach allows for the identification of the "signature" of the river on its pollution pattern at both coastal and littoral scales, highlighting the specific spatial footprint and dynamics of plastic dispersion associated with the river's outflow.

This detailed understanding provides essential guidance for policy-making and monitoring in environmentally sensitive areas, facilitating the design and implementation of more targeted strategies to reduce plastic pollution.

How to cite: Brandini, C., Mocali, R., Sacco, M., Bendoni, M., Doronzo, B., Tomei, E., Manetti, F., Taddei, S., Perna, M., and Solari, L.: Investigating River-Marine Interactions and Plastic Pollution Dynamics Using a Multimodel Approach to Support Policy Development in Environmentally Sensitive Areas, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20024, https://doi.org/10.5194/egusphere-egu25-20024, 2025.

12:05–12:15
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EGU25-17997
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ECS
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Virtual presentation
Assessing the Oceanic Role in Global PCB Dynamics: Secondary Emissions and Atmospheric Contributions (1930–2018) 
Vikas Kumar Meena and Asif Qureshi

Persistent Organic Pollutants (POPs) are a class of chemical compounds characterized by their persistence, bioaccumulation, long-range transport, lipophilicity, and toxicity. Due to their long half-lives and widespread distribution, understanding the fate of POPs is crucial. Traditionally, oceans have been considered significant sinks for POPs, where these pollutants accumulate and are sequestered over time. However, recent studies indicate that oceans also function as secondary sources, re-emitting POPs into the atmosphere through volatilization, sea surface spray, and other air-ocean exchange mechanisms. These secondary emissions contribute significantly to the atmospheric concentrations of POPs, influencing global transport and deposition patterns. In this study, we will use the BETR - Global model to quantify oceanic secondary emissions contribution to Polychlorinated Biphenyls (PCBs) atmospheric concentrations. The model incorporates oceanic PCB concentrations, air-sea exchange dynamics, and atmospheric transport to assess the ocean’s role in the sequestration and re-emission of these pollutants. The model has run from 1930 to 2018 for two congeners, PCB-28 and PCB-153. The results indicated that the ocean’s secondary emissions contributed 45.58% and 36.62% of PCB28 and PCB153, respectively, to the atmospheric emissions. Each year, oceans have emitted 2.77 × 104 and 1.18 × 104 kg (annual average during 1930 - 2018) of PCB28 and PCB153 into the atmosphere. Further simulations are planned to extract basin-wise secondary emissions and their contribution to atmospheric concentration. 

How to cite: Meena, V. K. and Qureshi, A.: Assessing the Oceanic Role in Global PCB Dynamics: Secondary Emissions and Atmospheric Contributions (1930–2018), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17997, https://doi.org/10.5194/egusphere-egu25-17997, 2025.

12:15–12:25
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EGU25-19752
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ECS
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On-site presentation
3D Lagrangian model to track fate and transport of plastic particles in the northern Adriatic Sea with a particular focus on physical and biogeochemical processes. 
Gaia Buccino, Celia Laurent, and Donata Canu

Plastics are a ubiquitous, global scarcely mapped pollutant that poses a particular threat to the marine ecosystem. Once they enter the oceans through sources such as estuaries and wastewater treatment plants, they are subjected to various environmental conditions that transport, fragment and scatter them, while altering their properties and exposing marine biota. These phenomena particularly threaten areas such as semi-enclosed basins where recirculation is limited. This is the case of the Adriatic Sea, a semi-enclosed basin with complex management challenges and strongly affected by marine plastic pollution due to significant anthropogenic pressure from intensive coastal activities, urbanization, and river inflows draining industrial northern Italy. In this study, we perform an analysis in this domain using a 3D Lagrangian-plastic model forced with physical and biogeochemical fields to simulate the direct transport of the plastic particles. We represent their interaction with biotic components, their transformations, alterations and the consequent changes in buoyancy. This approach allows us to investigate the particle’s presence, dynamics and role in the ecosystem, to identify potential accumulation areas, produce hazard maps highlighting the most vulnerable regions and quantify the individual contributions of each source.

 

How to cite: Buccino, G., Laurent, C., and Canu, D.: 3D Lagrangian model to track fate and transport of plastic particles in the northern Adriatic Sea with a particular focus on physical and biogeochemical processes., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19752, https://doi.org/10.5194/egusphere-egu25-19752, 2025.

Posters on site: Fri, 2 May, 14:00–15:45 | Hall X4

Display time: Fri, 2 May, 14:00–18:00
Chairpersons: George Zodiatis, Svitlana Liubartseva, Panagiota Keramea
X4.38
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EGU25-4174
Can we predict the next oil spill catastrophe in the Mediterranean? 
Svitlana Liubartseva, Giovanni Coppini, Pierre Daniel, Donata Canu, and Megi Hoxhaj

    The negative effects of oil spills on marine life, including plankton, fishes, aquatic birds, and mammals, can be devastating and long-lasting. Spilled oil emits toxic volatile chemicals into the atmosphere, fouls shorelines, and destroys commercial fisheries, aquaculture, and shellfish beds.

    Recognizing oil spill occurrence as a fundamentally random process, we carried out extensive Monte Carlo simulations using the Lagrangian MEDSLIK-II model (De Dominicis et al., 2013) to predict the impacts of future oil spill accidents in the Mediterranean.

    A historical HAVEN oil spill (off the Port of Genoa, 1991), known as the largest shipwreck in European waters and one of the most severe oil pollution incidents in the Mediterranean, was utilized for scenario prototyping. For the first time, virtual spills are sampled from contemporary long-term observational data for the entire Mediterranean Sea (Dong et al., 2022). To force MEDSLIK-II, we use the reanalyses provided by the Copernicus Marine Service and atmospheric wind data from ECMWF.

    Over two million simulated spills from 2018 to 2021 allow us to study conditional probability, assuming that a significant accidental oil spill, like the HAVEN disaster, may occur in the future at a specific location in the Mediterranean.

    In the results, we present maps of oil pollution hazard indices in probabilistic terms, statistical estimates of oil arrival time, the percentage of oil beached, and the budget for spilled oil mass.

    The Aegean Sea coastlines are among the most impacted areas, featuring elevated coastal hazard indices, short arrival times with a median value of about 3.1 days, and significant beached oil fractions of approximately 30%. In contrast, the Ionian, Central Mediterranean, and Levantine seas exhibit relatively low hazard indices, longer arrival times, and smaller beached oil percentages associated with the high dissipative properties of these sub-basins.

    The results obtained can be utilized for planning the exploration of offshore oil production fields and minimizing risks in maritime oil transfer activities.

    This work is performed in the framework of the NECCTON project (grant number 101081273).

 

    References

  • De Dominicis, M., Pinardi, N., Zodiatis, G., Lardner, R., 2013. MEDSLIK-II, a Lagrangian marine surface oil spill model for short term forecasting–part 1: Theory. Geosci. Model Dev. 6, 1851–1869.
  • Dong, Y., Liu, Y., Hu, C., MacDonald, I.R., Lu, Y., 2022. Chronic oiling in global oceans. Science 376, 1300–1304.

How to cite: Liubartseva, S., Coppini, G., Daniel, P., Canu, D., and Hoxhaj, M.: Can we predict the next oil spill catastrophe in the Mediterranean?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4174, https://doi.org/10.5194/egusphere-egu25-4174, 2025.

X4.39
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EGU25-6129
The modeling of oil pollution in the Kerch Strait in December 2024 
George Zodiatis, Hari Radhakrishnan, Andreas Nikolaidis, Dmitry Soloviev, and Kyriakos Prokopi

A serious maritime accident was caused in the Black Sea, when the hull of the tanker Volgoneft 212 broke at the southern entrance of the Kerch Strait around 06:00 GMT on December 15, 2024, about 4,000 tons of mazut fuel leaked. The weather at the time was very rough, with winds of up to 18 m/s and wave heights up to 3–5 m in the southern area of the Kerch Strait. It was reported from on-site observations that the oil spill during the first 3 days impacted an extended part of the southeastern coast, up to 60 km long from Veselovka to Anapa beaches. It was difficult to detect the oil spill extent using satellite SAR images, due to the limitations of such sensors under bad ocean conditions. However, a few SAR images were obtained by RadarSat and ESA on the 19th and 23rd of December 2024. Furthermore, there are several uncertainties concerning the location of the oil spill source and the time of the beginning of the oil discharge. The MEDSLIK oil spill model has been applied to predict the oil spill leakages using the Copernicus Marine Service Black Sea MFS currents, the SKIRON winds, and the CYCOFOS waves, considering a continuous oil leakage. Initially, for the oil spill predictions, the reported location of the tanker was used; however, the predicted impact on the coast did not correspond to the reported on-site observations. A new location was stochastically selected based on the AIS system locations, which shows the two bunkering zones of the vessels waiting before getting the approval to enter the strait. The oil spill predictions show a good agreement with the reported on-site observations regarding the impacted coastal areas, the large extent of the impacted coastal area, and the chronology of the oil deposition in the coastal area. The oil spill predictions confirm the deposition of the oil spillages on the touristic beaches between Veselovka and Blagoveshchensky, after first impacting the coast in the morning of December 17, 2024, i.e., 51-54 hours from the oil discharges, and of the Vitiazevo and Anapa beaches after first impacting the coast a few hours later in the morning of the same day, i.e., 54-57 hours from the oil discharges. At 22:00 GMT on December 17, 2024, i.e., 60-63 hours from the oil discharges, it was predicted the first impact on the coast from Anapa to Utrish. The SAR image obtained by RadarSat on the 19th of December 2024 at 16:00 GMT confirms the predicted impacted area between Anapa and Utrish. At 04:00 GMT in the early morning of December 20, 2024, the wind changed to strong southerly winds up to 8 m/s, contributing to the transfer of the oil spillage inside the strait, impacting first the cape Takil’ and then the western coastal area of the strait up to the port of Kerch. The SAR image obtained by ESA on 23 December 2024 at 03:45 GMT confirms the predicted impacted areas along the western coast of the Kerch Strait.

How to cite: Zodiatis, G., Radhakrishnan, H., Nikolaidis, A., Soloviev, D., and Prokopi, K.: The modeling of oil pollution in the Kerch Strait in December 2024, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6129, https://doi.org/10.5194/egusphere-egu25-6129, 2025.

X4.40
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EGU25-6967
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ECS
Impact of Water Column Stratification on Oil spill dispersion – Experimental simulations coupling glider data in the Thracian Sea
(withdrawn after no-show)
Panagiota Keramea, Nikolaos Kokkos, Felix Margirier, Stamatis Petalas, and Georgios Sylaios
X4.41
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EGU25-10959
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ECS
Underwater HNS Release: Modeling Gas Behavior  
Ludovic Lepers, Sébastien Legrand, Thomas Le Bihan, Laurent Aprin, and Stéphane Le Floc

The maritime transportation of Hazardous and Noxious Substances (HNS) continues to grow, posing significant risks to the marine environment and human health. In the event of an accidental release, these substances can create severe hazards, including toxic gas clouds, fires, and potential explosions. While existing models are effective for simulating conventional hydrocarbon spills, they lack the capability to accurately represent the complex behavior of volatile HNS released at sea. 

As part of the MANIFESTS-Genius European project, research has been conducted to advance knowledge in this area. A new module has been developed to simulate underwater gas releases, aiming to evaluate the quantity of gas dissolution as a gas plume rises through the water column from sources such as underwater pipelines or shipwrecks. By accurately modeling this process, it becomes possible to predict the characteristics of the gas cloud that may form at the surface. 

The module consists of a Python-based bubble rising and dissolution tracker. Its outputs can be used as standalone data or integrated into the OSERIT Lagrangian transport model, which is currently employed by the Belgian coastguard and member states of the Bonn Agreement. This integration enhances OSERIT's predictive capabilities for underwater gaseous releases by determining the initial distribution of HNS between the water column and the atmosphere. Consequently, this improvement strengthens decision-support tools used by responders to manage HNS-related incidents at sea. 

In this communication, we will present the processes implemented in the module, and how they have been validated using experimental data produced in the framework of the project. 

How to cite: Lepers, L., Legrand, S., Le Bihan, T., Aprin, L., and Le Floc, S.: Underwater HNS Release: Modeling Gas Behavior , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10959, https://doi.org/10.5194/egusphere-egu25-10959, 2025.

X4.42
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EGU25-11608
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ECS
Unravelling the pollution status of the Saronikos Gulf, Greece by investigating the chemical imprint of human-related activities in seawater and sediments, utilizing high resolution mass spectrometric workflows 
Rallis Lougkovois, Constantine Parinos, Georgios Gkotsis, Maria-Christina Nika, Alexandra Pavlidou, Ioannis Hatzianestis, and Nikolaos Thomaidis

Comprehensive monitoring of the marine environmental status of pollution is the first step towards unravelling the chemical imprint of anthropogenic activities. The EU’s strategy towards preserving the marine environment is facilitated by enacting relevant legislation, such as the Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). The EU-funded RHE-MEDiation project was launched to destress the Mediterranean Sea from chemical pollution, aiming to set the baseline of pollution close to areas considered as pollution “hotspots” and implement new technologies towards reducing the chemical impact of human-related activities onto the Mediterranean Sea. 

The Saronikos Gulf, Greece is highly impacted by activities of more than half of the Greek population. It specifically receives effluents from two wastewater treatment facilities, those of Psyttalia and Thriassio, as well as chemicals related to shipping activities from the port of Piraeus and the industrial zone of Elefsina. To assess the Gulf’s pollution status, the occurrence and distribution of more than 2,300 LC-amenable organic micropollutants was investigated in seawater and sediment samples. To that end, the technique of hybrid trapped ion mass spectrometry - quadrupole time-of-flight mass spectrometry (TIMS-QTOF-MS) was utilized. Wide scope target screening was employed on a database of more than 2,300 environmentally relevant chemicals including pharmaceuticals, coffee and tobacco related compounds, illicit drugs, artificial sweeteners, industrial chemicals, PFASs, plant protection products and surfactants, along with their respective metabolites and transformation products. 

Analysis results indicate the presence of polar organic compounds, such as pharmaceuticals and hydrophilic industrial chemicals in tested seawaters, a matrix to which they pose greater affinity than the non-polar sediment layer. For example, antiepileptics pregabalin and carbamazepine, along with the latter’s human consumption metabolite 10-hydroxy-carbamazepine were determined in concentrations up to 43.8ng/L, while a mixture of corrosion inhibitors 4- and 5-methyl-benzotriazole, as well as mercaptobenzothiazole were omnipresent in concentration levels ranging between 1.68 and 21.3 ng/L. 

In sediments tested, a variety of compounds with higher partition coefficient (log P) values, like lipophilic antibiotics, industrial chemicals and long-chain PFASs were determined. For example, legacy PFAS like perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were determined in concentration levels ranging ​​between 1.19 and 7.85μg/kg d.w. Semi-polar sulfonamide antibiotics sulfadiazine and sulfisoxazole were determined at concentrations up to 0.378 μg/kg d.w. Their presence can be attributed to their persistent nature, considering that their administration has diminished in recent years, due to their adverse side effects on human health. Possible pathways by which hydrophobic compounds are concentrated in the sediment compartment may include repelling effects by the aqueous seawater layer, although sorption effects onto microplastics, followed by precipitation has also been reported in the literature. 

This work was funded by the European Union’s HORIZON EUROPE Research and Innovation Program under Grant Agreement No: 101113045 ‘RHE-MEDiation Responsive hub for long term governance to destress the Mediterranean Sea from chemical pollution’. 

How to cite: Lougkovois, R., Parinos, C., Gkotsis, G., Nika, M.-C., Pavlidou, A., Hatzianestis, I., and Thomaidis, N.: Unravelling the pollution status of the Saronikos Gulf, Greece by investigating the chemical imprint of human-related activities in seawater and sediments, utilizing high resolution mass spectrometric workflows, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11608, https://doi.org/10.5194/egusphere-egu25-11608, 2025.

X4.43
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EGU25-13523
Historical Pollution and the Risk of Heavy Metal Remobilization in Coastal Sediments of Barcelona 
Josep Roqué-Rosell, Harmen Sebastiaan Johannes Hogenhuis, Jaime Frigola, Carlo Marini, Marc Cerdà-Domènech, Paula Del Rio-Gómez, and Miquel Canals

Industrial activity in the Besòs River watershed has historically contributed to significant heavy metal pollution in coastal sediments near Barcelona. While mitigation measures implemented since the 1980s have effectively reduced contamination in surface sediments, deeper layers remain polluted. Increasing societal and economic pressures, along with episodic natural disturbances, could remobilize these stored pollutants, posing environmental and public health risks.

The GeoCr-BCN project investigates heavy metal pollution in sediments from the Besòs and Llobregat river prodeltas, with a focus on chromium (Cr). Sediment cores were analyzed using X-ray fluorescence core scanning (XRF-CS) to quantify heavy metal concentrations. Additionally, X-ray absorption spectroscopy (XAS) at the ALBA Synchrotron was employed to determine Cr speciation, providing insights into its geochemical behavior and potential toxicity under different environmental conditions.

Preliminary findings indicate significant heavy metal contamination in Besòs cores, with distinct stratification separating older, anthropogenic layers from more recent, less contaminated sediments. In contrast, Llobregat cores show minimal heavy metal presence, reflecting differences in industrial and hydrological inputs. XAS analysis reveals that Cr is primarily found in its reduced form, forming less toxic compounds. However, sediment disturbance and reoxygenation could mobilize Cr and shift it to more toxic, and bioavailable forms.

These results underscore the effectiveness of past environmental policies while highlighting ongoing risks associated with sediment destabilization. High-energy events, such as storms, can exceed treatment capacities, leading to temporary increases in metal deposition. Moreover, societal and economic developments that disrupt sediment layers could exacerbate pollution risks.

This study emphasizes the need for continuous monitoring of heavy metals in coastal sediments and for sustainable, evidence-based policy decisions to ensure the long-term ecological and environmental stability of the Barcelona coastal shelf.

How to cite: Roqué-Rosell, J., Hogenhuis, H. S. J., Frigola, J., Marini, C., Cerdà-Domènech, M., Del Rio-Gómez, P., and Canals, M.: Historical Pollution and the Risk of Heavy Metal Remobilization in Coastal Sediments of Barcelona, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13523, https://doi.org/10.5194/egusphere-egu25-13523, 2025.

X4.44
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EGU25-15976
Investigation of marine plastic pollution and socioeconomic impacts in the area of Pachia Ammos, Crete 
George Alexandrakis, John Karagiorgos, Vasiliki Metheniti, George Kozyrakis, Vassilios Vervatis, Sofianos Sarantis, and Nikolaos Kampanis

This extended abstract addresses the issue of marine plastic pollution in the Pachia Ammos area, Crete, and explores the potential for developing an early warning system specifically for marine litter. The research area is located in East Crete, Greece, and spans from Pachia Ammos to Tholos Kavousi, focusing on Pachia Ammos and Voulisma beaches. The methodology integrates field sampling and numerical modeling to assess plastic debris distribution and movement patterns. Data collection involved onshore and offshore sampling, physical documentation, and classification of waste. Hydrodynamic models, NEMO 3D and OceanParcels, were employed to simulate the dispersion of plastic debris based on historical oceanographic data. The results revealed significant seasonal variations in plastic pollution, with increased accumulation during summer months due to tourism and calm weather. As main pollution types macroplastics such as bottles, caps, and fishing gear were identified especially during storm events. Hydrodynamic modeling identified both local sources and long-range influx from the Eastern Aegean region. The results show a significant influence of regional and transboundary pollution sources and also seasonal fluctuations align with increased tourist activity and calmer sea states. By applying dedicated downscaled climate projections and hydrodynamic simulations for predicting pollution hotspots and incorporating machine learning and predictive modeling there is a possibility to identify key future events to issue alerts for pollution risk. This study underscores the importance of developing an early warning system specifically for marine plastic pollution using hydrodynamic modeling and data-sharing frameworks. By integrating predictive tools and community involvement, the system can support proactive management and pollution mitigation strategies. Collaboration among policymakers, scientists, and local stakeholders is crucial for effective coastal resilience.

How to cite: Alexandrakis, G., Karagiorgos, J., Metheniti, V., Kozyrakis, G., Vervatis, V., Sarantis, S., and Kampanis, N.: Investigation of marine plastic pollution and socioeconomic impacts in the area of Pachia Ammos, Crete, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15976, https://doi.org/10.5194/egusphere-egu25-15976, 2025.

X4.45
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EGU25-17826
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ECS
Lagrangian tracking of river microplastics in the Mediterranean Basin 
Lisa Weiss, Claude Estournel, Patrick Marsaleix, Guillaume Mikolajczak, Mel Constant, and Wolfgang Ludwig

The Mediterranean Sea, a semi-enclosed basin with highly anthropized coastlines, intense marine traffic and significant river discharges, has been identified as a plastic pollution hotspot. However, the quantification of sources, transfers and accumulations remains variable, and simulated marine plastic cycles are still incomplete. In this study, we applied a recent river microplastic source scenario (Weiss et al., 2021, Science) to Mediterranean river basins. This enabled Lagrangian dispersion simulations to be initiated using high-resolution 3D current fields (including atmospheric, tidal, wave and river forcing) performed with the SYMPHONIE hydrodynamic model and its Lagrangian module (Weiss et al., 2024a,b, ESPR). Modeled concentrations of floating and sinking particles were analyzed, simulating a wide range of vertical velocities. A coherent regional 3D dispersion scenario allowed to establish a mass balance of microplastic fluxes, from river sources to coastal stranding in the different sub-basins. Results revealed a massive export of floating particles from the northwestern to the southeastern sub-basins, with residence times ranging from 1-3 weeks in dissipative zones to 11 weeks in convergent zones. Comparison of modeled and observed surface stocks suggested the need to introduce missing sources and sinks, as fragmentation or sedimentation, and to reduce stranding probabilities (by about 30%). A seasonal analysis of the microplastic dispersion from the Rhône River plume (the largest freshwater discharge in the Mediterranean) in the SYMPHONIE simulations highlighted the influence of hydrodynamic conditions on particle transfer. It included dispersion patterns on the continental shelf of the Gulf of Lion and the frontal zone from the Pyrenees to the North Balearic fronts, demonstrating the role of fine-scale circulation in shaping concentration gradients.

How to cite: Weiss, L., Estournel, C., Marsaleix, P., Mikolajczak, G., Constant, M., and Ludwig, W.: Lagrangian tracking of river microplastics in the Mediterranean Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17826, https://doi.org/10.5194/egusphere-egu25-17826, 2025.

X4.46
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EGU25-17860
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ECS
WITOIL service in the context of Digital Twins - Bridging Oil spill simulations from Medslik-II into digital cloud domains 
Igor Atake, Juliana Ramos, Santiago Bravo, Anusha Dissanayake, Giovanni Coppini, and Gianandrea Mannarini

WITOIL (Where Is The Oil http://www.witoil.com), has been developed to maintain emergency management in case of an oil spill accident. Currently more and more initiatives are integrating traditional modeling systems into Digital Twins (DT’s) and in this context it was done the same for oil spill simulations. The usage of DT systems enables advanced environmental management and emergency response, since they provide close to real-time monitoring, simulation, and analysis, offering tools to predict and manage complex scenarios effectively. WITOIL is containerized through Docker, encapsulating Python workflows, integration scripts, and the MEDSLIK-II model (FORTRAN 90) into scalable environments. This approach ensures portability, efficiency, and reliability for deployment in platforms like iMagine and EDITO.

On the iMagine platform (https://www.imagine-ai.eu/case-study/oil-spill-detection-oil-spill-detection-from-satellite-images), WITOIL-for-iMagine by using Bayesian optimization, the MEDSLIK-II model achieves enhanced accuracy for spill behavior predictions. Users can launch simulations and access results quickly, combining remote sensing past data with modeling in a streamlined workflow for pollution analysis. The system represents one of the first approaches on merging traditional oil spill simulations and machine learning techniques that were applied in the optimisation process.

The EDITO Model Lab (https://edito-modellab.eu/) presents WITOIL-Cloud as a decision support system for oil spill emergency management. It integrates the MEDSLIK-II model, operational meteo-oceanographic services (Copernicus Marine Services and Climate Data Store). With a user-friendly interface, stakeholders can simulate oil spill trajectories and impacts in historical scenarios, enabling informed decision-making. The system’s accessibility democratizes advanced modeling tools, expanding their reach to diverse users.

WITOIL-Cloud's integration of real-time environmental data ensures accuracy and relevance in emergency responses. A real-world case study via the EDITO Model Lab and iMagine platform exemplifies this capability. It was chosen the Syria 2021 oil spill case as an example of usage on both DT to demonstrate the platform capabilities, showing how the platforms could support on future events by exemplifying on a real past scenario

By connecting traditional models with digital twin platforms, WITOIL enhances oil spill modeling's accessibility, and efficiency. These innovations empower stakeholders to address maritime pollution challenges with easier access, quicker response of digital twins in shaping the future of environmental management and emergency response in the case of oil spill accidents.

How to cite: Atake, I., Ramos, J., Bravo, S., Dissanayake, A., Coppini, G., and Mannarini, G.: WITOIL service in the context of Digital Twins - Bridging Oil spill simulations from Medslik-II into digital cloud domains, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17860, https://doi.org/10.5194/egusphere-egu25-17860, 2025.

X4.47
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EGU25-18380
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ECS
Determination of the long-term chemical impact of human-related activities on the Red Sea coastal marine environment utilizing complementary mass spectrometric techniques and novel chemometric tools 
Panagiota Kontogianni, Rallis Lougkovois, Ioannis Hatzianestis, Georgios Gkotsis, Maria-Christina Nika, Constantine Parinos, Yasser Abualnaja, Nikolaos Thomaidis, and Alexandra Pavlidou

Comprehensive environmental monitoring of chemical pollution is the initiative towards providing information regarding the quality of marine ecosystems. Compounds such as pharmaceuticals, industrial chemicals, PFAS, PAHs PCBs, and plant protection products often end up in environmental substrates following a number of different pathways. Upon reaching the sea, biotic and abiotic processes may take place, producing metabolites and transformation products, which often pose an even greater threat to the marine environment than their parent compounds. This leads to further degradation of aquatic ecosystems and inevitably affects human health. 

The marine environment of the Red Sea is a cornerstone in the development of the Arabic Peninsula, contributing to its constant economic growth. Continuous urbanization and industrialization on its coasts lead to unavoidable chemical encumbrance. To address this matter, the Kingdom of Saudi Arabia has launched the Marine and Coastal Environment Protection Initiative to evaluate the current state of the coastal Red Sea area. Existing lagoons act as large banks of sedimentation, where precipitation takes place, potentially burdening sediments and benthic seawaters with lipophilic organic micropollutants, volatile organic compounds and heavy metals. This process occurs likely due to sorption mechanisms onto microplastics, as previously reported in the literature, followed by precipitation, which is enhanced by said contaminants’ non-affinity with the aqueous seawater compartment. Besides sea bottom degradation, polluted sediments become potential sources of seawater recontamination, increasing the number of emerging contaminants (ECs) to which marine organisms are exposed to. 

Aiming to determine a wide variety of existing emerging contaminants in surface sediments collected from 52 stations along the Red Sea coastal zone, generic sample preparation workflows and complementary analytical techniques were applied. ECs of various physicochemical properties were determined by utilizing GC-LRMS (volatile organic substances) and LC-HRMS (wide-scope target screening) techniques. An in-house developed dataset of more than 2,400 analytes was applied for said determinations. 

Preliminary results indicate that the Red Sea lagoons are chemically encumbered by different groups of pollutants, based on different point sources existing in the vicinity. Pharmaceutically active compounds as well as a wide variety of pollutants linked to industrial activity, such as PFAS, PAHs and PCBs were determined. Numerous compounds determined are linked to industrial and wastewater treatment facilities’ discharges, as well as maritime transportation and port activities. Utilization of analytical methods and instrumental techniques which cover different chemical groups provides the ability to determine a wide variety of pollutants, facilitating a holistic approach on the baseline of pollution, while also allowing more robust environmental monitoring. 

How to cite: Kontogianni, P., Lougkovois, R., Hatzianestis, I., Gkotsis, G., Nika, M.-C., Parinos, C., Abualnaja, Y., Thomaidis, N., and Pavlidou, A.: Determination of the long-term chemical impact of human-related activities on the Red Sea coastal marine environment utilizing complementary mass spectrometric techniques and novel chemometric tools, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18380, https://doi.org/10.5194/egusphere-egu25-18380, 2025.

X4.48
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EGU25-15739
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ECS
Maxey-Riley advection leads to enhanced spatial variability of buoyant macroplastic on the north-west European shelf seas 
Meike F. Bos, Irina I. Rypina, Larry J. Pratt, and Erik van Sebille

Macroplastics (plastic objects > 5 cm) make up most of the mass of plastic in the ocean. Most plastic enters the ocean in the form of macroplastic to only later fragment into microplastic. Thus, cleaning up macroplastic is potentially an effective way to prevent microplastic pollution in the ocean. However, the distribution of macroplastic varies widely in space and time, especially in coastal regions where most macroplastic enters the ocean. What processes cause this large variability is not yet understood.

In our study, we investigate how the “inertia” of macroplastic affects their trajectories. For this, we use Lagrangian analysis. Most commonly in Lagrangian analysis, plastic particles are advected with the fluid flow, sometimes with an additional windage term and added vertical velocity due to particles' buoyancy. However, due to the finite size and positive buoyancy of macroplastics, this simplified approach does not fully describe their movement: instead, their motion is governed by the Maxey-Riley equations. These equations describe the motion of particles in a fluid as a result of the forces working on these particles. In this work we include the effects of inertia, viscous drag, added mass and the Coriolis acceleration. We implemented the Maxey-Riley equations in OceanParcels, allowing simulation of the trajectories of a large number of particles in surface 2D ocean flows. Using this implementation, we study the Maxey-Riley effects on the trajectories of the particles. Here, we focus on gaining understanding under what conditions the trajectories and accumulation patterns of buoyant inertial particles deviate from tracer particles, where we investigate both the role of the characteristics of the ocean flow and particle properties (i.e., size and buoyancy).

As most macroplastic enters the ocean in coastal areas, we chose to study the effect of their finite size and positive buoyancy on their trajectories in the north-west European shelf. We find that the Coriolis forces in the Maxey-Riley equations affect the surface 2D accumulation pattern of macroplastic. Compared to the accumulation patterns of tracer particles, we find enhanced accumulation in specific areas under specific conditions. Thus, the large observed spatial variability of macroplastic might partly be explained by the Coriolis effect coupling to the finite size and positive buoyancy of the particles.

How to cite: Bos, M. F., Rypina, I. I., Pratt, L. J., and van Sebille, E.: Maxey-Riley advection leads to enhanced spatial variability of buoyant macroplastic on the north-west European shelf seas, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15739, https://doi.org/10.5194/egusphere-egu25-15739, 2025.

X4.49
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EGU25-21049
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ECS
Seasonal Variability and Land-Sea Interactions of PFAS in the Beibu Gulf: Insights from Machine Learning
(withdrawn after no-show)
Yan Lin and Luo Nemin
X4.50
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EGU25-11639
Marine litter pollution in the Western Mediterranean: new insights from the OBAMARAN project 
Javier Soto-Navarro, Jorge Ramos-Alcántara, and Gabriel Jordà

Marine litter (ML) pollution has become a major concern in the Mediterranean, a semienclosed basin that receives large amounts of pollution from its highly populated coasts. However, there are concerns about how reliable is the picture we have at present about this problem. In particular, the amount of existing ML and the ML sources are key aspects that have not been yet completely clarified. In the context of the OBAMARAM project, which aims to characterize the origin and evolution of marine debris along the southern Spanish coastline, a series of studies have been conducted that offer novel insights into those key aspects. Initially, a series of observing system simulation experiments (OSSE) were conducted to assess the capabilities of different monitoring strategies to estimate the average concentration of marine litter in the Western Mediterranean within an acceptable range of uncertainty. The results demonstrate that conventional sampling strategies are inadequate for reliable estimation of temporal averages and spatial means at the basin or sub-basin scale. However, these strategies can be representative of spatial averages at the synoptic scale in smaller regions.

Subsequently, a comprehensive survey of available marine litter observations in all compartments of the western Mediterranean marine environment was made. For this purpose, 180 scientific publications were analyzed. Moreover, several open access databases were consulted to collect data on the abundance of plastics on the sea surface in the region, gathering information from more than 800 net trawls conducted during the period between 2011 and 2022. The results were then used to produce concentration maps based on observations and a homogenized surface sampling database. The study's primary finding is that the available observations are inadequate in characterizing the concentration of marine debris in the basin, given its dispersion both spatially and temporally. Additionally, there is a lack of coordination and standardization in the measurement techniques, which complicates data homogenization and intercomparison.

After this, the problem of the identification of ML sources has been addressed for the Balearic Islands, where a homogeneous and continuous database is available in time. Here, observations from cleaning campaigns were combined with numerical simulations to generate an inverse model that allows estimating the origin of marine litter collected in different regions of the coast of the archipelago. This approach has allowed to identify the main areas of ML disposal, although the uncertainties are significant and has some limitations that will be discussed in the presentation.

Finally, a very high resolution numerical study has been designed to parameterize the ML import and export between the nearshore and the open sea. The main goal is to identify under what conditions there is an effective transfer of ML from the coast to the open sea. This will help in the identification of ML sources.

How to cite: Soto-Navarro, J., Ramos-Alcántara, J., and Jordà, G.: Marine litter pollution in the Western Mediterranean: new insights from the OBAMARAN project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11639, https://doi.org/10.5194/egusphere-egu25-11639, 2025.