Six contaminants of emerging concern (CECs): clarithromycin, citalopram, tributylphosphate, benzotriazole, octocrylene and teflubenzuron, with differing sources, applications, and contrasting properties were selected for modeling their fate in the water column and the sediments of the Oslofjord. The FABM family models was used, which couples the benthic-pelagic model 2DBP with the biogeochemical model BROM and the elaborated contaminants transformation module. This approach parameterized processes of CECs partitioning with organic matter, and CECs decay due to biodegradation, photolysis, and hydrolysis. This combination of modules allows for the simulation of spatial and temporal variability of CECs 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 CECs from the sediments; (iii) after cessation of the pollution a flux of dissolved CECs from the sediments was predicted for a certain period; (iv) properties of the CECs determine the effectiveness of the biological pump and duration of CECs existence in the water column and the sediments following the cessation of pollution.

Plastic pollution monitoring programs use a wide array of methods, protocols, and analytical approaches, making it difficult for researchers and practitioners to determine which techniques to apply, where, and how. This lack of harmonisation across environmental compartments and plastic size classes has led to inconsistent data and limited comparability across studies. To address this, a systematic review of monitoring methods from 1960 to 2021 was conducted, encompassing both peer-reviewed and grey literature. Techniques were categorised into Reproducible Analytical Pipelines (RAPs), each comprising six core steps: survey design, sample collection, sample preparation, analytical detection, quantification, and data reporting. Each RAP was assessed using Technological Readiness Levels (TRLs) to evaluate maturity and suitability for standardised monitoring. The review revealed that while robust and repeatable methods exist, they are inconsistently applied. At the time of this review, atmospheric plastics was underrepresented, highlighting a critical gap in monitoring efforts. The findings underscore the urgent need for a global, objective framework to guide the selection and implementation of plastic pollution monitoring methodologies. This paper lays the foundation for such a framework by presenting a methodology to identify mature, reproducible methods and prioritise areas for further development. Future work should focus on harmonising protocols across compartments and size classes, improving transparency in data reporting, and building consensus around standardised practices to enable global comparability and policy relevance.

Plastic pollution has become a central concern for researchers, policymakers, and the public, particularly in light of the negotiations for the Global Plastics Treaty in Geneva in 2025. Over the past two decades extensive research has greatly improved our understanding of the severity of microplastic pollution through occurrence and impact studies. Recently, the focus has shifted from quantifying plastic abundance toward assessing the potential risks and impacts of microplastics on environmental, animal, and human health. Compared to marine, estuarine, and freshwater ecosystems, research on terrestrial ecosystems remains limited. The scarcity of monitoring data makes it hard to assess the current and future ecological risk of microplastic pollution. This lack of data, largely due to methodological challenges, introduces considerable uncertainty in evaluating the effects of microplastics on the environment. Regardless of the studied ecosystem, assessing microplastic risk is inherently complex. A single plastic polymer may contain hundreds of chemical additives (e.g. plasticizers, pigments), adsorb additional pollutants (e.g. pesticides), and even act as a vector for pathogenic organisms. Furthermore, potential effects depend not only on concentration but also on the polymer type, particle size distribution, and morphology. In this reflection paper, we examine these challenges and propose pathways toward more objective microplastic risk assessments.

As offshore wind energy undergoes rapid expansion, understanding the ecotoxicological risk of infrastructurerelated chemical stressors, such as anticorrosion paint leachates, is vital for regional environmental management. This study investigated the acute physiological effects of leachates of paints commonly applied in North Sea offshore wind farms on the key bioindicator Mytilus edulis. Mussels were exposed for 14 days under three conditions: in direct contact with painted steel plates (direct exposure), near painted plates (indirect exposure), and in uncontaminated seawater (control). Physiological parameters including oxygen consumption, clearance rate, and ammonia excretion, were measured to derive the scope for growth (SFG), an integrative indicator of energy balance. Results showed no statistically significant difference in SFG or individual physiological rates across treatments. Mean SFG values (f SD) were 20.6 f 12.2, 21.2 f 10.4 and 20.2 f 11.5 J h- 1 g- 1 for control, direct and indirect exposures, respectively. These findings suggest that current anticorrosion coatings do not pose an immediate acute risk to adult M. edulis, even at concentrations exceeding expected offshore dilution. Although chronic exposure assessments and early life-stage studies incorporating molecular biomarkers remain critical gaps, this research provides essential baseline data to support environmental risk assessment and monitoring frameworks for the North Sea's offshore wind sector.

Seafloor litter is an applied indicator for the assessment of marine pollution. Harmonized seafloor litter categorization is essential for quality assured assessments. This study aimed to assess the quality of seafloor litter classification and the effectiveness of the International Council for Exploration of the Sea (ICES) seafloor litter categorization guidelines through an online proficiency test. Participants classified pictures of seafloor litter from trawls based on the ICES manual and photo guide. The test identified correlations between users’ experience and classification accuracy. Findings demonstrated participants had a good ability to classify seafloor litter items based on the guidelines with an average accuracy rate of 83

Offshore wind farms (OWFs) play a crucial role in reducing carbon emissions and fossil fuel dependence, and their expansion is essential for meeting European energy and climate targets. Understanding their ecological impact is therefore essential. While many environmental impacts of OWFs are systematically monitored, chemical emissions remain largely overlooked. To address this gap, sediment samples were collected within and around OWFs in the Belgian and German parts of the North Sea, along with reference samples from three types of reference sites. Non-target screening using GC-MS-EI and LC-HRMS-ESI± detected over 8000 compounds. Most of these compounds were omnipresent in the whole study area, but more than 1000 showed significantly higher abundance inside OWFs. Tentative identification suggests that some of these compounds originate from epoxy and polyurethane coatings. These findings suggest that OWFs contribute to the release of chemicals into the environment. However, the impact and effects of these chemicals are still unknown.

The offshore wind energy sector is experiencing rapid and large-scale expansion in Europe, driven by increasingly ambitious renewable energy targets that position it as a central component of global climate mitigation efforts. The increasing number of offshore wind projects in the North Sea requires comprehensive regulations to monitor and minimize the impacts on the marine environment during construction, operation and decommissioning. This policy brief aims to summarize current regulations for chemical emissions in the North Sea area by reviewing available national documents and websites for guidance in Belgium, Denmark, France, Germany, the Netherlands, and Norway in combination with information received from respective authorities. Based on the collected information, the policy brief will give recommendations for potential harmonization to increase the protection of the environment and facilitate procedures. The comparative analysis of national and transnational regulations for chemical emissions from offshore wind farms in North Sea bordering countries revealed that these are incomplete and differ between countries in terms of their specifications and level of detail. For example, specific rules for the application of galvanic anodes including the ban of zinc-based anodes are only available in Germany while several but not all countries prohibit the use of antifouling or other toxic paints. Incompleteness and differences may also be related to a lack of information on substances and their environmental effects. To achieve harmonization and more efficient protection of the marine environment, more data and minimum requirements on a regional level will be necessary, while at the same time, innovation may not be hampered and design and techniques should be further optimized and adapted based on latest available information.

Offshore wind energy may offer many advantages: next to the aim of renewable energy production, offshore wind farms (OWFs) enable multi-purpose opportunities with nature conservation and aquaculture. OWFs may also affect the marine ecosystem. The environmental impact of OWFs is starting to be investigated regarding the effect of novel habitat introduction, underwater noise, electromagnetic fields, or exclusion of fisheries. However, the impact of chemical emissions from OWFs remains largely unknown. It is essential to account for these emissions at an early stage, to comprehensively assess the environmental impact with the objective of developing a future fit-for-purpose regulatory framework to protect the marine environment. This review compiled a literature-based list of potential OWF-related chemical emissions containing >200 organic and inorganic contaminants, including polymers. Compounds are categorised according to data source and emission type. Major gaps in assessing the impact of the compounds are identified, including challenges in environmental monitoring, numerical modelling and assessing the toxicity of individual and mixtures of chemical contaminants on marine organisms and humans consuming potential OWF aquaculture products. A risk-based prioritisation is essential to target the compounds of higher concern and overcome costs linked to assessing a wide variety of chemical contaminants. Although some countries have regulations to reduce OWF chemical emissions, standardized impact assessments or monitoring requirements for OWF-based chemical contaminants have not been established. This stresses the importance of providing more detailed information on occurrence, distribution and impact of OWF chemical emissions as an essential step towards sound ecosystem-based management of OWF installations.

Little is known about the exposure of aquatic biota to tire and road wear particles (TRWP) washed away from roads. Mussels were exposed for 7 days to model TRWP (m-TRWP), produced by milling tire tread particles with pure sand, and analyzed for 21 tire-related compounds by liquid chromatography-high resolution-mass spectrometry (LC-HRMS). Upon exposure to 0.5 g/L of m-TRWP, 15 compounds were determined from 944 μg/kg wet weight (diphenylguanidine, DPG) over 18 μg/kg for an oxidation product of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6-PPDQ) to 0.6 μg/kg (4-hydroxydiphenyl amine). Transfer into mussels was highest for PTPD, DTPD and 6-PPDQ and orders of magnitude lower for 6-PPD. During 7 days depuration the concentration of all determined chemicals decreased to remaining concentrations between ~50 % (PTPD, DTPD) and 6 % (6-PPD). Suspect and non-target screening found 37 additional transformation products (TPs) of tire additives, many of which did not decrease in concentration during depuration, among them ten likely TPs of DPG, two of 6-PPD and PTPD and two of 1,2-dihydro-2,2,4-trimethylquinoline. A wide variety of chemicals is taken up by mussels upon exposure to m-TRWP and a wide range of TPs is formed, enabling the differentiation of biomarkers of exposure to TRWP and biomarkers of exposure to tire-associated chemicals.

The Horizon Europe project, CONTRAST, will develop an integrated assessment and effect-based monitoring framework (IAF) to measure the impacts of contaminants of emerging concern (CECs) on the marine environment, which will contribute to the assessment of Good Environmental/ Ecological Status for application in EU policy (MSFD/WFD). The IAF will involve chemical measurements together with biological effects endpoints optimised to detect the presence and effect of CECs in the marine environment. Chemical prioritisation schemes will identify the CECs that pose the greatest threat to marine life and select which CECs to target in the laboratory experiments, where the effects on organisms and biodiversity will be assessed. In silico, in vitro and in vivo bioassays will be used to determine the mechanisms of toxicity of selected CECs. Providing information on how CECs interact with organisms at environmentally relevant concentrations and which biological effects tools should be used in the IAF to cover the range of toxicity mechanisms that CECs produce. A series of European-wide case studies will be used to test the suitability of the IAF to measure the effects of chemicals including CECs on indicator species and biodiversity and to model fate of CECs in marine environment. The knowledge gained from field testing and laboratory studies will form the basis for guidance documents and policy briefs on best practices for performing an IAF on CECs in the marine environment and help to provide the necessary protection of marine ecosystems.

Increasing numbers of chemicals with little-known adverse effects are released into the marine environment. The present study addresses the lack of marine-specific prioritisation schemes by developing a prioritisation tool for organic contaminants. This tool supports decision-making processes regarding which chemicals to study further in terms of their occurrences and biological effects in the marine environment. It was supported by a database containing approximately 1.13 million chemicals, developed within the PikMe project. Criteria for chemical prioritisation were identified by a comprehensive literature review, then selected using the outcomes of a survey among experts. The prioritisation tool consists of filtering chemicals in the PikMe database using three parallel schemes—persistence and bioaccumulation, toxicity, and persistence and mobility characteristics (step 1)—followed by scoring based on modes of action, occurrence, and emission (step 2) and ranking by the final score (step 3). Around 8000 chemicals were selected by filtering (step 1). The top 100 resulted from step 3 comprises 6PPD as the highest-ranked compound and other chemicals with high diversity of uses, e.g. pharmaceuticals as the predominant category of use, industrial chemicals, personal care products, flame retardants, and plastic additives. These chemicals were ranked in the top 100 due to dominant influence of diverse prioritisation criteria. Using the hazard-based approach that encompasses different adverse effects that contaminants of emerging concern can exert, the marine-specific prioritisation tool can guide decision-making in monitoring, ecotoxicological studies, and regulations regarding contaminants of emerging concern in the marine environment.

Monitoring the movement of plastic into marine food webs is central to understanding and mitigating the plastic pollution crisis.

An intercomparison exercise on “microplastics in sediment” was carried out by five laboratories using samples collected in the Bay of Marseille in September 2021. The results from different extraction and identification methods varied depending on the type and size classes of MPs, and was better than 80 % for the size class >300 μm and for the fragments. The variability in recovery rates can be attributed to the choice of reagents and extraction protocols. Recovery rates per laboratory were between 47 % and 113 % and the use of ZnCl2 and NaI increased recovery rates by an average of 70 %. The lowest recovery rates (47 and 53 %) were attributed to the reference methods (FTIR and LDIR), conversely the highest (80 and 87 %) were attributed to identification by Nile Red. The average ranged between 23 and 53 items /50 g d.w. with decreases offshore and at greater depth.

Despite the urgent need for accurate and robust observations of microplastics in the marine environment to assess current and future environmental risks, existing procedures remain labour-intensive, especially for smaller-sized microplastics. In addition to this, microplastic analysis faces challenges due to environmental weathering, impacting the reliability of research relying on pristine plastics. This study addresses these knowledge gaps by testing the robustness of two automated analysis techniques which combine machine learning algorithms with fluorescent colouration of Nile red (NR)-stained particles. Heterogeneously shaped uncoloured microplastics of various polymers—polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC)—ranging from 100 to 1000 µm in size and weathered under semi-controlled surface and deep-sea conditions, were stained with NR and imaged using fluorescence stereomicroscopy. This study assessed and compared the accuracy of decision tree (DT) and random forest (RF) models in detecting and identifying these weathered plastics. Additionally, their analysis time and model complexity were evaluated, as well as the lower size limit (2–4 µm) and the interoperability of the approach. Decision tree and RF models were comparably accurate in detecting and identifying pristine plastic polymers (both > 90

Plastics are persistent in the environment and may be ingested by organisms where they may cause physical harm or release plastic additives. Monitoring is a crucial mechanism to assess the risk of plastics to the marine and terrestrial ecosystem. Unfortunately, due to unharmonised procedures, it remains difficult to compare the results of different studies. This publication, as part of the Horizon project EUROqCHARM, aims to identify the properties of the available analytical processes and methods for the determination of plastics in biota. Based on a systematic review, reproducible analytical pipelines were examined and the technological readiness levels were assessed so that these methods may eventually (if not already) be incorporated into (harmonised) monitoring programs where biota are identified as indicators of plastic pollution.

The availability of many microplastic analysis methods is challenging for researchers and policy makers when tasked with choosing optimal methods for their research question and a given budget. In this study, a cost-effectiveness analysis of methods for microplastic analysis in seawater was performed using survey data acquired from experts. Total analysis cost per method was determined accounting for labour and equipment costs, while method effectiveness was scored based on their ability to confirm the plastic nature of particles, their minimum detectable particle size, and other parameters. Results were validated and discussed during two workshops with scientists and policy makers. The resulting predictive tools allow to identify the most cost-effective methods for specific scenarios, and their associated cost. They mark an important step towards a more effective and informed approach to monitoring and managing microplastic pollution in the marine environment, ultimately contributing to the protection of marine ecosystems and human health.

Microplastic (MP) research faces challenges due to costly, time-consuming, and error-prone analysis techniques. Additionally, the variability in data quality across studies limits their comparability. This study addresses the critical need for reliable and cost-effective MP analysis methods through validation of a semi-automated workflow, where environmentally relevant MP were spiked into and recovered from marine fish gastrointestinal tracts (GITs) and blue mussel tissue, using Nile red staining and machine learning automated analysis of different polymers. Parameters validated include trueness, precision, uncertainty, limit of quantification, specificity, sensitivity, selectivity, and method robustness. For fish GITs a 95 ± 9 % recovery rate was achieved, and 87 ± 11 % for mussels. Polymer identification accuracies were 76 ± 8 % for fish GITs and 80 ± 13 % for mussels. Polyethylene terephthalate fragments showed more variability with lower accuracies. The proposed validation parameters offer a step towards quality management guidelines, as such aiding future researchers and fostering cross-study comparability.

Marine litter and non-degradable plastic pollution is of global concern. Regular monitoring programs are being established to assess and understand the scale of this pollution. In Europe, the goal of the European Marine Strategy Framework Directive (MSFD) is to assess trends in Good Environmental Status and support large-scale actions at the regional level. Marine litter monitoring requires tailored sampling strategies, protocols and indicators, that align with specific objectives and are tailored for local or regional needs. In addition, the uneven spatial and temporal distributions of marine litter present a challenge when designing a statistically powerful monitoring program. In this paper, we critically review the existing marine litter monitoring programs in Europe. We discuss the main constraints, including environmental, logistical, scientific, and ethical factors. Additionally, we outline the critical gaps and shortcomings in monitoring MSFD beaches/shorelines, floating litter, seafloor litter, microplastics, and harm. Several priorities must be established to shape the future of monitoring within the MSFD. Recent developments in analytical approaches, including optimizing protocols and sampling strategies, gaining a better understanding of the spatiotemporal heterogeneity of litter and its implications for survey design and replication, and the inclusion of newly validated methodologies that have achieved sufficient technical readiness, must be considered. Although there are well-established methods for assessing beaches, floating and seafloor litter, it will be necessary to implement monitoring schemes for microplastics in sediments and invertebrates as robust analytical methods become available for targeting smaller particle size classes. Furthermore, the inclusion of indicators for entanglement and injury to marine organisms will have to be considered in the near future. Moreover, the following actions will enhance the effectiveness of monitoring efforts: (1) creating an inventory of accumulation areas and sources of specific types of litter (e.g., fishing gear), (2) monitoring riverine inputs of litter, (3) monitoring atmospheric inputs including microplastics, (4) accidental inputs during extreme weather events, and (5) studying how species at risk may be transported by litter. We provide recommendations to support long-term, effective, and well-coordinated marine litter monitoring within the MSFD to achieve a comprehensive and accurate understanding of marine litter in EU waters. This will allow the development of measures to mitigate the impacts of marine pollution and eventually to evaluate the success of the respective measures.

Determining the extent of pollution in the marine environment remains challenging. Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals can, during dredging operations, be transported from a port or harbour into the open sea, where they may exert a harmful effect on the marine ecosystem. To fully understand the impact of these chemicals, monitoring programs should not only focus on sediment concentrations, but should also take into account the bioaccumulated concentration in the tissue of multiple target organisms. In this study, the concentration of primary contaminants is determined in common starfish (Asterias rubens), flying crab (Liocarcinus holsatus), and brown shrimp (Crangon crangon) and the difference in the concentration of contamination between different dredge disposal sites at open sea is investigated. Different factors such as lipid weight, dry weight, grain size, and total organic carbon were measured and used to understand the difference between the observed bioaccumulation and the measured sediment concentrations. KEY MESSAGE: Different contaminants are detected in biota such as common starfish, flying crab and brown shrimp. These contaminants can be linked to dredging activities, with disposal sites associated with industrial ports showing higher contamination.

The growing demand of seafood alternatives is driven by concerns on overfishing, marine pollutants and animal welfare in aquaculture and fisheries. Currently, the availability of non-animal-based seafood flavorings on the market is limited, and animal-based seafood flavorings conflict with vegetarian and vegan criteria.The aim of this study is to explore the use of Tetraselmis chuii as a seafood flavoring in a vegetable broth. The flavor of the T. chuii broth was compared with a broth containing vegan fish flavoring based on a yeast extract and two broths containing white fish and lobster flavorings. To evaluate the different broths, the study employs a combination of sensory evaluation by a trained panel, chemical flavor analysis for aroma and umami characteristics, and consumer acceptability tests.Our results indicate that T. chuii effectively imparts a fish and shellfish flavor to the broth, which is less intense compared to the white fish and lobster flavorings. Nevertheless, consumers are equally positive of the aroma and flavor of the T. chuii broth and the animal-based seafood flavorings broths. The chemical flavor analysis of the T. chuii broth identifies volatile organic compounds (VOCs) such as dimethyl sulfide, methanethiol, trimethylamine, and 4-heptenal (Z), which collectively contribute to its distinct seafood aroma.Consumer preference tests show a preference for the seafood aroma of the T. chuii broth over the vegan fish flavoring broth, attributed to the meaty-like off-odor originating from specific VOCs of the yeast extract. In contrast, the vegan fish flavoring broth exhibits a stronger umami taste which is explained by elevated levels of free glutamate and guanosine-5′-monophosphate.This study highlights the potential of T. chuii as innovative seafood flavoring agent to enhance the sensory experience of seafood alternatives, contributing to the ongoing development of sustainable and flavorful non-animal alternatives in the food industry.