A recipe for plastic: Expert insights on plastic additives in the marine environment.

The production and consumption of plastic products had been steadily increasing over the years, leading to more plastic waste entering the environment. Plastic pollution is ubiquitous and comes in many types and forms. To enhance or modify their properties, chemical additives are added to plastic items during manufacturing. The presence and leakage of these additives, from managed and mismanaged plastic waste, into the environment are of growing concern. In this study, we gauged, via an online questionnaire, expert knowledge on the use, characteristics, monitoring and risks of plastic additives to the marine environment. We analysed the survey results against actual data to identify and prioritise risks and gaps. Participants also highlighted key factors for future consideration, including gaining a deeper understanding of the use and types of plastic additives, how they leach throughout the entire lifecycle, their toxicity, and the safety of alternative options. More extensive chemical regulation and an evaluation of the essentiality of their use should also be considered.

Leaving a plastic legacy: Current and future scenarios for mismanaged plastic waste in rivers.

Mismanaged plastic waste (MPW) entering the riverine environment is concerning, given that most plastic pollution never reaches the oceans, and it has a severe negative impact on terrestrial ecosystems. However, significant knowledge gaps on the storage and remobilization of MPW within different rivers over varying timescales remain. Here we analyze the exposure of river systems to MPW to better understand the sedimentary processes that control the legacy of plastic waste. Using a conservative approach, we estimate 0.8 million tonnes of MPW enter rivers annually in 2015, affecting an estimated 84 % of rivers by surface area, globally. By 2060, the amount of MPW input to rivers is expected to increase nearly 3-fold, however improved plastic waste strategies through better governance can decrease plastic pollution by up to 72 %. Currently, most plastic input occurs along anthropogenically modified rivers (49 %) yet these represent only 23 % of rivers by surface area. Another 17 % of MPW occur in free-flowing actively migrating meandering rivers that likely retain most plastic waste within sedimentary deposits, increasing retention times and likelihood of biochemical weathering. Active braided rivers receive less MPW (14 %), but higher water discharge will also increase fragmentation to form microplastics. Only 20 % of plastic pollution is found in non-migrating and free-flowing rivers; these have the highest probability of plastics remaining within the water column and being transferred downstream. This study demonstrates the spatial variability in MPW affecting different global river systems with different retention, fragmentation, and biochemical weathering rates of plastics. Targeted mitigation strategies and environmental risk assessments are needed at both international and national levels that consider river system dynamics.

Microplastic pollution in the intertidal and subtidal sediments of Vava'u, Tonga.

Plastic pollution research on a global scale intensified considerably in the current decade; however, research efforts in the South Pacific are still lagging. Here, we report on microplastic contamination of intertidal and subtidal sediments in the Vava'u archipelago, Tonga. While providing the first baseline data of its type in Tonga, the study also advances methods and adjusts them for low-budget research. The methods were based on density separation of microplastics from the sediment using CaCl2, a high-density salt which due to its high solubility, low cost and availability. Once separated, microplastics were quantified by microscopic analysis and polymers characterized via FTIR spectroscopy. Microplastics in intertidal and subtidal sediments were found in concentrations of 23.5 ± 1.9 and 15.0 ± 1.9 particles L-1 of sediment, respectively. The dominant type of microplastics in both intertidal (85 %) and subtidal sediments (62 %) were fibres.

Microplastic pollution in the surface waters of Vava'u, Tonga.

Marine plastic pollution, particularly microplastics, has been recognised as a global issue in the recent years, but research efforts in the Pacific are lagging. We carried out research on microplastics contamination of surface waters of the Vava'u archipelago, Tonga. Since microplastics smaller than the standard mesh size (333-335 µm) are readily reported in the literature on microplastics, we used a finer plankton net (100 µm) to determine the proportion of captured microplastics smaller than 300 µm. Isolated microplastics were counted and measured using stereomicroscope with polymer identification performed by FTIR spectroscopy. The analysis revealed high microplastics concentrations (329,299.7 ± 40,994.2 pcs km-2 or 1.05 ± 0.13 pcs m-3). The proportion of particles smaller than 300 µm was 40 %. The predominant type of microplastics in surface waters were small bits of white film, which we associated with cement-filled white bags used to construct docks throughout Vava'u, often heavily eroded.

E-waste it wisely: lessons from Africa.

E-waste is the world's fastest growing and most valuable domestic waste stream. The increasing production of e-waste is driving elevated levels of export from developed to developing countries. Although countries worldwide are actively recognising the issues around e-waste and introducing policies, legislation or regulations governing e-waste, a large fraction of e-waste, goes undocumented at its end-of-life. Much of the global e-waste is accumulating in open dumpsites in several African countries. Using available data, we calculate the total e-waste in Africa (locally produced plus imported e-waste) for 2019 to be between 5.8 and 3.4 metric tonnes (Mt). This is believed to be an underestimate, large data gaps exist, hindering more precise estimates. The data is further complicated by, sometimes intentional, differences in labelling and reporting between formal and intermittent informal importers. Based on the available data, the main African recipients of e-waste are Nigeria, Ghana, and Tanzania, with Kenya, Senegal and Egypt featuring as countries of concern. The lack of proper waste management in the recipient developing countries, leads to environmental contamination and human exposure. A coordinated, regional and global, approach is needed in tackling e-waste. Regulatory frameworks, together with monitoring and compliance mechanisms need to be developed, financed, and enforced.

Meso- and microplastics monitoring in harbour environments: A case study for the Port of Durban, South Africa.

An investigation into the abundance and distribution of meso- and microplastics within the Port of Durban was conducted using a static immersible water pump and particle filtration system to collect meso- and microplastics from the water column, microplastics from sediment samples and corresponding CTD. Microplastics were detected in all samples under investigation. Results suggest that sewage overflow, stormwater drains, port operations, followed by rivers are input areas for mitigation to focus on. Identifying meso- and microplastics inputs, baselines and distribution allow for long term monitoring and management in a harbour environment. This can potentially contribute to the control and regulation of small plastics particles in harbours, and the subsequent transport of these pollutants via dredged material into other ecosystems.

Occurrence and abundance of meso and microplastics in sediment, surface waters, and marine biota from the South Pacific region.

Data on the occurrence and abundance of meso and microplastics for the South Pacific are limited and there is urgent need to fill this knowledge gap. The main aim of the study was to apply a rapid screening method, based on the fluorescence tagging of polymers using Nile red, to determine the concentration of meso and microplastics in biota, sediment and surface waters near the capital cities of Vanuatu and Solomon Islands. A spatial investigation was carried out for sediment, biota and water as well as a temporal assessment for sediment for two consecutive years (2017 and 2018). Accumulation zones for microplastics were identified supported by previous hydrodynamic models. Microplastics were detected for all environmental compartments investigated indicating their widespread presence for Vanuatu and Solomons Islands. This method was in alignment with previous recommendations that the Nile red method is a promising approach for the largescale mapping of microplastics in a monitoring context.

Shades of grey: Marine litter research developments in Europe.

European research efforts to address concerns in relation to increasing levels of marine litter and potential effects on ecosystems and human health have been launched. We assessed a total of 52 European projects which researched or contributed to the implementation of European marine litter legislation. These projects ranged from national initiatives, to large scale programmes involving multiple EU member states. The best represented topics within those European projects were 'Policy, Governance and Management' and 'Monitoring'. Comparatively 'Risk Assessment', 'Fragmentation' and 'Assessment Tools' were underrepresented. The analyses showed that West-European countries have contributed more to marine litter research and therefore received more funding. As a result, thematic hotspots were present, and scientific capacity is concentrated by topic and countries. The results indicate the need to continue to support initiatives to cover clearly identified gaps, either geographic or thematic, to deliver risk assessments and recommendations to address the marine litter issue.

Exploring public views on marine litter in Europe: Perceived causes, consequences and pathways to change.

Marine litter is a global challenge and society plays an important role via lifestyles and behaviour, including policy support. We analysed public perceptions of marine litter and contributing factors, using data from 1133 respondents across 16 European countries. People reported high levels of concern about marine litter, and the vast majority (95%) reported seeing litter when visiting the coast. The problem was attributed to product and packaging design and behaviour rather than lack of facilities or accidental loss of items. Retailers, industry and government were perceived as most responsible, but also least motivated and competent to reduce marine litter, whereas scientists and environmental groups were perceived as least responsible but most motivated and competent. Regression analyses demonstrated the importance of psychological factors such as values and social norms above sociodemographic variables. These findings are important for communications and interventions to reduce inputs of marine litter to the natural environment.

Polycyclic Aromatic Hydrocarbons (PAHs) and Hopanes in Plastic Resin Pellets as Markers of Oil Pollution via International Pellet Watch Monitoring.

Oil pollution in the marine environment is an unavoidable problem due to chronic input from local sources, particularly in urban areas and oil spills. Oil pollution not only causes immediate physical damages to surrounding wildlife but also some components, including higher molecular weight PAHs, can persist in the environment for many years and pose insidious threats to the ecosystem. Long-term and nontargeted monitoring of oil pollution is important. This paper examines the ability of International Pellet Watch (IPW) for initial identification and monitoring of oil pollution by analysing PAHs and hopanes in plastic pellet samples collected globally by volunteers. PAH concentrations with the sum of 28 parent and methyl PAHs vary geographically, ranging from 0.035 to 24.4 µg/g-pellet, in line with the presence or absence of local oil pollution sources, such as oil refineries or oil spill sites. This suggests that PAHs can be used to monitor petroleum pollution in IPW. A colour-coded categorization for PAH concentrations within IPW monitoring also is established to facilitate data presentation and understanding. PAH concentrations are generally higher in Western Europe, especially around the North Sea shorelines, moderate in East Asia and North America, and lower in South East Asia, Oceania, South America, and Africa. Hopane concentrations, with a smaller spatial variation (1.7-101 µg/g-pellet), showed no spatial pattern. This result and the poor correlation between hopanes and PAHs suggest that hopane concentrations alone are unsuited to identify petroleum pollution. However, hopane compositions can be used for fingerprinting sources of oil pollution. Thus, both PAHs and hopanes in IPW allow for low cost, remote monitoring of global oil pollution.

A rapid-screening approach to detect and quantify microplastics based on fluorescent tagging with Nile Red.

A new approach is presented for analysis of microplastics in environmental samples, based on selective fluorescent staining using Nile Red (NR), followed by density-based extraction and filtration. The dye adsorbs onto plastic surfaces and renders them fluorescent when irradiated with blue light. Fluorescence emission is detected using simple photography through an orange filter. Image-analysis allows fluorescent particles to be identified and counted. Magnified images can be recorded and tiled to cover the whole filter area, allowing particles down to a few micrometres to be detected. The solvatochromic nature of Nile Red also offers the possibility of plastic categorisation based on surface polarity characteristics of identified particles. This article details the development of this staining method and its initial cross-validation by comparison with infrared (IR) microscopy. Microplastics of different sizes could be detected and counted in marine sediment samples. The fluorescence staining identified the same particles as those found by scanning a filter area with IR-microscopy.

Integrated indicator framework and methodology for monitoring and assessment of hazardous substances and their effects in the marine environment.

Many maritime countries in Europe have implemented marine environmental monitoring programmes which include the measurement of chemical contaminants and related biological effects. How best to integrate data obtained in these two types of monitoring into meaningful assessments has been the subject of recent efforts by the International Council for Exploration of the Sea (ICES) Expert Groups. Work within these groups has concentrated on defining a core set of chemical and biological endpoints that can be used across maritime areas, defining confounding factors, supporting parameters and protocols for measurement. The framework comprised markers for concentrations of, exposure to and effects from, contaminants. Most importantly, assessment criteria for biological effect measurements have been set and the framework suggests how these measurements can be used in an integrated manner alongside contaminant measurements in biota, sediments and potentially water. Output from this process resulted in OSPAR Commission (www.ospar.org) guidelines that were adopted in 2012 on a trial basis for a period of 3 years. The developed assessment framework can furthermore provide a suitable approach for the assessment of Good Environmental Status (GES) for Descriptor 8 of the European Union (EU) Marine Strategy Framework Directive (MSFD).

Concentrations of mercury and other trace elements in porbeagle shark Lamna nasus.

Concentrations of 11 trace elements in three tissues of porbeagle shark Lamna nasus (n=33) were determined. The maximum observed concentrations of Cd and Pb in muscle were 0.04 and 0.01mgkg-1, respectively, and all muscle samples were below European seafood limits for these metals. Hg concentrations in either the red or white muscle that exceeded European regulations for seafood were observed in one-third of specimens. Hg concentration, however, increased with length, and all fish >195cm had concentrations >1.0mgkg-1, with a maximum observed value of 2.0mgkg-1. Concentrations of Fe and Cu were, on average, 9.7 and 10 times higher in red muscle than in nearby white muscle, respectively. Mn, Zn, As and Se were also found in significantly higher concentrations in red muscle than in white muscle.

Enhancing public awareness and promoting co-responsibility for marine litter in Europe: The challenge of MARLISCO.

Marine litter is a pervasive and complex societal problem but has no simple solution. Inadequate practices at all levels of production-use-disposal contribute to accumulation of waste on land and at sea. Enhanced societal awareness but also co-responsibility across different sectors and improved interactions between stakeholders are necessary. MARLISCO was a European initiative, which developed and implemented activities across 15 countries. It worked towards raising societal awareness and engagement on marine litter, through a combination of approaches: public exhibitions in over 80 locations; a video competition involving 2100 students; and a legacy of educational and decision-supporting tools. 12 national participatory events designed to facilitate dialogue on solutions brought together 1500 stakeholders and revealed support for cross-cutting, preventive measures. Evaluation during implementation shows that these activities are effective in improving individuals' perceptions about the problem but also commitment in being part of the solution. This paper summarises MARLISCO's approach and highlights a selection of outcomes.

Microplastic contamination in brown shrimp (Crangon crangon, Linnaeus 1758) from coastal waters of the Southern North Sea and Channel area.

This study assessed the capability of Crangon crangon (L.), an ecologically and commercially important crustacean, of consuming plastics as an opportunistic feeder. We therefore determined the microplastic content of shrimp in shallow water habitats of the Channel area and Southern part of the North Sea. Synthetic fibers ranging from 200µm up to 1000µm size were detected in 63% of the assessed shrimp and an average value of 0.68±0.55microplastics/g w. w. (1.23±0.99microplastics/shrimp) was obtained for shrimp in the sampled area. The assessment revealed no spatial patterns in plastic ingestion, but temporal differences were reported. The microplastic uptake was significantly higher in October compared to March. The results suggest that microplastics >20µm are not able to translocate into the tissues.

Organohalogen contaminants and trace metals in North-East Atlantic porbeagle shark (Lamna nasus).

The North-East Atlantic porbeagle (Lamna nasus) population has declined dramatically over the last few decades and is currently classified as 'Critically Endangered'. As long-lived, apex predators, they may be vulnerable to bioaccumulation of contaminants. In this study organohalogen compounds and trace elements were analysed in 12 specimens caught as incidental bycatch in commercial gillnet fisheries in the Celtic Sea in 2011. Levels of organohalogen contaminants were low or undetectable (summed CB and BDE concentrations 0.04-0.85 mg kg(-1)wet weight). A notably high Cd concentration (7.2 mg kg(-1)wet weight) was observed in one mature male, whereas the range observed in the other samples was much lower (0.04-0.26 mg kg(-1)wet weight). Hg and Pb concentrations were detected only in single animals, at 0.34 and 0.08 mg kg(-1)wet weight, respectively. These contaminant levels were low in comparison to other published studies for shark species.