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The release of plastics into aquatic ecosystems and their effects within food webs is a growing concern. Plastic ingestion in animals such as bivalves, fish, birds, and mammals are established areas of study, but the effects of plastics on smaller animals, such as zooplankton and larval fish, are not as readily observed. Additionally, primary ingestion of plastic directly from the water is only one route of accumulation of plastic. We examined secondary ingestion of microplastics from zooplankton to larval fish in a model laboratory system. Rotifer (Branchionus plicatilis) readily accumulated 6 µm plastic microspheres in a concentration and time dependent manner. Larval zebrafish (Danio rerio) also ingested free plastic from the water, but the greatest uptake of plastic was seen to be ingested through secondary ingestion of plastic-fed rotifer. These experiments present a model experimental system in which to study secondary ingestion and movement of microplastics between feed and prey.

The global accumulation of plastic waste has reached crisis levels. The diverse and multilayered impacts of plastic on biological health prompts an evaluation of these effects from a One Health perspective, through which the complexity of these processes can be integrated and more clearly understood. Plastic particles ranging from nanometers to meters in size are found throughout every ecosystem on Earth, from the deepest marine trenches to the highest mountains. Plastic waste affects all layers of biological organization, from the molecular and cellular to the organismal, community, and ecosystem-levels. These effects are not only mediated by the physical properties of plastics, but also by the chemical properties of the plastic polymers, the thousands of additives combined with plastics during manufacturing, and the sorbed chemicals and microbes that are transported by the plastic waste. Using a One Health framework we provide an overview of the following themes: 1) ways in which plastic impacts global health across levels of biological organization, 2) how the effects of plastic interact between layers of biology, and 3) what knowledge gaps exist in understanding the effects of plastic within and between biological scales. We also propose potential solutions to address this growing crisis, with an emphasis on One Health perspectives that consider the oneness of animals, humans, and the environment.

We have applied a multispecies ecosystem approach to analyse the ingestion of anthropogenic particles (AP) in the gastrointestinal tract of 313 individuals (17 fish species and 8 invertebrate species) from pelagic, demersal and benthic habitats in a marine protected area off the Western Mediterranean (Cabrera National Park). We have quantified and characterized the ingestion at several taxonomic levels of fish, sea urchins, sea cucumbers, bivalves, and jellyfish in relation to biotic/abiotic factors based on taxonomic groups, trophic guilds (functional groups) and habitats. AP ingestion occurrence ranged from 26 to 100% with no significant differences among taxonomic groups. The fish within the MPA showed an overall ingestion occurrence ranging from 0 to 100%, the echinoderms from 29 to 100%, the bivalves from 72 to 96% and the jellyfish 36% ingestion. The ecosystem approach applied to evaluate overall AP ingestion within the species reported that for trophic guilds, the omnivorous species ingested the highest amounts of anthropogenic items, while herbivores ingested significantly fewer items than all other trophic guilds. Moreover, no significant differences were found amongst habitats, indicating a homogeneous spatial distribution of APs at all studied habitats. The multispecies approach provided insight into the high APs exposure to species within Cabrera MPA, highlighting the potential harm linked with marine litter that threatens marine biodiversity., SI

Plastic debris is a ubiquitous pollutant on the sea surface. To date, substantial research efforts focused on the detection of plastic accumulation zones. Here, a different paradigm is proposed: looking for crossroad regions through which large amounts of plastics debris flow. This approach is applied to the Mediterranean Sea, massively polluted but lacking in zones of high plastic concentration. The most extensive dataset of plastic measurements in this region to date is combined with an advanced numerical plastic-tracking model. Around 20% of Mediterranean plastic debris released every year passed through about 1% of the basin surface. The most important crossroads intercepted plastic debris from multiple sources, which had often traveled long distances. The detection of these spots could foster understanding of plastic transport and help mitigation strategies. Moreover, the general applicability and the soundness of the crossroad approach can promote its application to the study of other pollutants. Also see: https://micro2022.sciencesconf.org/426899/document, In MICRO 2022, Online Atlas Edition: Plastic Pollution from MACRO to nano

The increasing global concern surrounding plastic marine pollution has placed a spotlight on the key items identified as major contributors. The subsequent public outcry has forced key value-chain actors – such as brand owners, retailers and restaurateurs – to be seen to be responding to the issue. However, are their responses motivated by a true desire for environmentalism or are actors engaging in greenwashing? In this case study on plastic straws, the brand owners and retailers interviewed are driven by a desire to meet consumer expectations. This desire has led to the substitution of plastic straws with glass, paper and polylactide alternatives. However, the broader environmental implications of the alternatives are rarely considered. This single-minded focus on marine pollution has the potential to result in inadvertent greenwashing as alternative products may result in more harm in other environmental compartments.Significance: The increasing concern surrounding plastic pollution has placed a spotlight on key items, forcing plastic value-chain actors to respond. The broader environmental impacts of the interventions are rarely considered, resulting in the potential for adoption of products which may result in increased harm in other environmental compartments.

Marine plastic is a prolific issue concerning the world’s oceans, yet methods of detecting and quantifying the true extent are not yet fully developed. However, remote sensing detection of plastic litter is currently in its foundation, although it is still necessary to realise the most effective process. Presently, regarding passive remote sensing, both satellite and airborne methods have been trialled. UAV remote sensing for plastic detection proves a cost-efficient method in which differing approaches of machine learning detection have been trialled. Of the methods, object-based image analysis (OBIA) has not yet been examined. Therefore, using eCognition software, UAV RGB imagery was tested using OBIA to test the accuracy of the results using sensitivity, positive predictive value and F-Score. Conversely, scoring 57.9%, 1.2% and 2.2% respectively, the method of OBIA is dissected for flaws in order to improve for the future, where larger sample sizes and multispectral imagery is suggested.

Plastic debris carry fouling a variety of class-size organisms, among them harmful microorganisms that potentially play a role in the dispersal of allochthonous species and toxic compounds with ecological impacts on the marine environment and human health. We analyzed samples of marine plastics floating at the sea surface using a molecular qPCR assay to quantify the attached microalgal taxa, in particular, harmful species. Diatoms were the most abundant group of plastic colonizers with maximum abundance of 8.2 x 10(4) cells cm(-2) of plastics, the maximum abundance of dinoflagellates amounted to 1.1 x 10(3) cells cm(-2) of plastics. The most abundant harmful microalgal taxon was the diatom Pseudo-nitzschia spp., including at least 12 toxic species, and the dinoflagellate Ostreopsis cf. ovata with 6606 and 259 cells cm(-2), respectively. The abundance of other harmful microalgal species including the toxic allochthonous dinoflagellate Alexandrium pacificum ranged from 1 to 73 cells cm(-2). In the present study, a direct relationship between the abundance of harmful algal species colonizing the plastic substrates and their toxin production was found. The levels of potential toxins on plastic samples ranged from 101 to 10(2) ng cm(-2), considering the various toxin families produced by the colonized harmful microalgal species. We also measured the rate of adhesion by several target microalgal species. It ranged from 1.8 to 0.3 day(-1) demonstrating the capacity of plastic substrate colonizing rapidly by microalgae. The present study reports the first estimates of molecular quantification of microorganisms including toxin producing species that can colonize plastics. Such findings provide important insights for improving the monitoring practice of plastics and illustrate how the epi-plastic community can exacerbate the harmful effects of plastics by dispersal, acting as an alien and toxic species carrier and potentially being ingested through the marine trophic web. (C) 2018 Elsevier Ltd. All rights reserved.

Since its third phase (dated 2016), EMODnet Chemistry's scope of attention has been expanded with gathering data and developing access to data and data products for Marine Litter. This document gives background information about EMODnet strategy for marine litter (beach and seafloor) data collection, its synergy with existing information systems and achievements of EMODnet Chemistry so far. Thereafter it gives detailed information on how to deal with marine litter data from beaches and seafloor trawlings and, in particular, the formats to be used for gathering and describing this type of marine litter data sets by EMODnet Chemistry participants on a European scale. Published We acknowledge the fundamental contribution of EMODnet Chemistry Steering Committee and Technical Working Group, MSFD Technical Subgroup on Marine Litter, Regional Sea Conventions (OSPAR, HELCOM, UNEP/MAP Barcelona Convention, BSCS Black Sea Commission), ICES, ARPA FVG, CEFAS. We also acknowledge the contribution of the following EU-projects: BASEMAN, PERSEUS, MEDITS, DeFishGear, EMBLAS. Refereed Current 14.1 Marine debris Mature International Method Specification of criteria

Since its third phase (dated 2016), EMODnet Chemistry's scope of attention has been expanded with gathering data and developing access to data and data products for Marine Litter. This document gives background information about EMODnet strategy for marine litter (beach and seafloor) data collection, its synergy with existing information systems and achievements of EMODnet Chemistry so far. Thereafter it gives detailed information on how to deal with marine litter data from beaches and seafloor trawlings and, in particular, the formats to be used for gathering and describing this type of marine litter data sets by EMODnet Chemistry participants on a European scale. Published We acknowledge the fundamental contribution of EMODnet Chemistry Steering Committee and Technical Working Group, MSFD Technical Subgroup on Marine Litter, Regional Sea Conventions (OSPAR, HELCOM, UNEP/MAP Barcelona Convention, BSCS Black Sea Commission), ICES, ARPA FVG, CEFAS. We also acknowledge the contribution of the following EU-projects: BASEMAN, PERSEUS, MEDITS, DeFishGear, EMBLAS. Refereed Current 14.1 Marine debris Mature International Method Specification of criteria

This document includes the Mission Statement and the Terms of Reference of the Task Force on Remote Sensing of Marine Litter and Debris of the International Ocean-Colour Coordinating Group (IOCCG). The Task Force has as an overarching goal to coordinate the advancement of current and future remote sensing technologies and techniques that have potential to provide observations of marine plastic litter over all aquatic environments. Considering all remote sensing technologies (with a special focus on radiometric approaches), the Task Force aims to promote a unified interdisciplinary international team of remote sensing experts with the goal to coordinate the development of traceable and transparent approaches for detecting, identifying, quantifying and tracking requirements of plastic litter. These requirements will be supported by four interlinked core topics that are the foundation pillars of the Task Force; (i) technologies, (ii) algorithms and applications, (iii) datasets and (iv) interdisciplinary aspects.

Plastic debris in the coastal environment is subject to complex and poorly characterized weathering processes. To better understand how key environmental factors affect plastic degradation in a coastal zone, we conducted an in situ experiment. We deployed strips of high density polyethylene (HDPE) and polystyrene (PS) in paired coastal areas of contrasting conditions (hydrodynamic activity: erosional or depositional; water depths: subtidal or intertidal). Strips were collected after environmental exposures at 4, 8, and 43 weeks and analyzed for change in mass, algal biofilm growth, and imaged by petrographic and electron microscopy (SEM-EDS). Significant surface erosion was evident on both polymers, and was more rapid and more extensive with PS. Degradation of PS was responsive to intensity of hydrodynamic activity, and was greater at intertidal depths, highlighting the critical role played by photo-oxidation in the coastal zone, and suggesting that algal biofilms may slow degradation by playing a photo-protective role.

As part of the 3rd phase of EMODnet Chemistry, the scope of attention has been expanded with gathering data and developing access to data and data products for marine litter. This document gives background information about EMODnet strategy for marine litter data collection, its synergy with existing information systems and achievements of EMODnet Chemistry so far. Thereafter it gives detailed information on how to deal with marine litter data for the scope of the EMODnet Chemistry 3 project and, in particular, the formats to be used for gathering and describing marine litter data sets by EMODnet Chemistry participants on a European scale. Published We acknowledge the fundamental contribution of EMODnet Chemistry Steering Committee and Technical Working Group, MSFD Technical Subgroup on Marine Litter, Regional Sea Conventions (OSPAR, HELCOM, UNEP/MAP Barcelona Convention, BSCS Black Sea Commission), ICES, ARPA FVG, CEFAS. We also acknowledge the contribution of the following EU-projects: BASEMAN, PERSEUS, MEDITS, DeFishGear, EMBLAS. Current 14.1 TRL 1 Basic principles observed and reported Manual (incl. handbook, guide, cookbook etc)

The transport of plastic particles from inland sources to the oceans garbage patches occurs trough coastal regions where the transport processes depend highly on wave‐induced motions. In this study, experimental measurements of the plastic particles wave‐induced Lagrangian drift in intermediate water depth are presented investigating the influence of the wave conditions, particle size and density on the motion of relatively large plastic particles. A large influence of the particle density is observed causing particles to float or sink for relative densities lower and larger than water respectively. The measured net drift of the floating particles correlates well with theoretical solutions for particle Stokes drift, where the net drift is proportional to the square of the wave steepness. Floating particles remain at the free water surface because of buoyancy and no evidence of any other influence of particle inertia on the net drift is observed. Nonfloating particles move close to the bed with lower velocity magnitudes than the floating particles’ motion at the free surface. The drift of nonfloating particles reduces with decreasing wave number, and therefore wave steepness., Key Points A 16 m wave flume is used to measure wave transport of floating and non‐floating plasticFloating plastic transport correlates well with Stokes drift and buoyancy is the only non‐inertial effectNon‐floating particles experience shear forces. Transport varies with particle size and density

12 Pág. Centro de Investigación en Sanidad Animal (CISA), Microplastics (MPs) in the Arctic have raised increasing concern, but knowledge on MP contamination in benthic organisms from Arctic shelf regions, e.g., the Chukchi Sea is still limited. Therefore, the present study investigated the occurrence, characteristics, sources, and environmental implications of MPs in the three most common benthic species, namely sea anemone (Actiniidae und.), deposit-feeding starfish (Ctenodiscus crispatus), and snow crab (Chionoecetes opilio), from the Chukchi Sea. The abundances of MPs in the three benthic species were significantly greater than those from the Bering Sea, but lower than those from other regions globally. The top three compositions of MPs in the three species were polyester, nylon, and polyethylene terephthalate. The detection limit for MP size in the present study was 0.03 mm and the mean size of MP in the three species was 0.89 ± 0.06 mm. The surfaces of MPs found in the starfish and crabs were covered with many attachments, cracks, and hollows, while the surfaces of MPs found in the sea anemones were smooth, which was likely a consequence of different feeding behaviors. There was a significantly positive correlation between the abundances of MPs and other anthropogenic substances. The mean MP abundances in the sea anemones ranged from 0.2 items/individual to 1.7 items/individual, which was significantly higher than that in the deposit-feeding starfish (0.1-1.4 items/individual) and snow crabs (0.0-0.6 items/individual). Sea anemones inhabiting lower latitudes ingested relatively higher levels of MPs than those inhabiting higher latitudes. The MP abundances in the sea anemones are significantly and positively correlated with the seasonal reduced ratio of sea ice coverage from August to September. Our findings indicate that sea anemones could function as a bioindicator of MP pollution, and that the MPs in the benthos from the Chukchi Sea might originate from the melting sea ice, fishery activities and ocean currents., This work was sponsored by the Scientific Research Foundation of the Third Institute of Oceanography, Ministry of Natural Resources (No. 2018019), the Chinese Arctic and Antarctic Administration, the Ninth Chinese National Arctic Research Expedition (9th CHINARE-Arctic), the National Key Research and Development Program of China (No. 2019YFD0901101), the National Natural Science Foundation of China (Nos. 41977211 and 41722605), and the National Program on Global Change and Air-Sea Interaction (GASI-02-SCS-YDsum). CB was funded by SNF Post Doc Mobility Fellowship number P400PB_183824.

Marine plastic pollution has become a prominent environmental issue in the recent years. Plastic ingestion is of special concern, as its magnitude and consequences for marine organisms and potentially humans are still largely unknown. We reviewed 93 papers on plastic ingestion by wild marine fish published since 1972. Plastic ingestion was detected in 323 (65%) of 494 examined fish species, and in 262 (67%) of 391 examined commercial fish species. These proportions are likely greater, as a detailed analysis of the sampling effort and analytical methods used in the reviewed studies suggests an underestimation of plastic ingestion in some assessments. A significant positive relationship (R = + 0.845, p = 0.004) was found between the sample size up to N = 10 and the detection of plastic ingestion. We also found significant differences in detection and frequency of occurrence (FO, %) of plastic ingestion among the three main types of analytical methods: naked-eye, microscopic analysis and chemical digestion. The chemical digestion method, which is also the most robust laboratory method, had the greatest detection (86%) and the highest FO (37.6 +/- 0.6%). To avoid the underestimation of plastic ingestion in future work, we provided recommendations for sample sizes and laboratory analysis.

Floating plastic debris is an increasing source of pollution in the world's oceans. Numerical simulations using models of ocean currents give insight into the transport and distribution of microplastics in the oceans, but most simulations do not account for the oscillating flow caused by global barotropic tides. Here, we investigate the influence of barotropic tidal currents on the transport and accumulation of floating microplastics, by numerically simulating the advection of virtual plastic particles released all over the world's oceans and tracking these for 13 years. We use geostrophic and surface Ekman currents from GlobCurrent and the currents caused by the four main tidal constituents (M 2, S 2, K 1, and O 1) from the FES model. We analyze the differences between the simulations with and without the barotropic tidal currents included, focusing on the open ocean. In each of the simulations, we see that microplastic accumulates in regions in the subtropical gyres, which is in agreement with observations. The formation and location of these accumulation regions remain unaffected by the barotropic tidal currents. However, there are a number of coastal regions where we see differences when the barotropic tidal currents are included. Due to uncertainties of the model in coastal regions, further investigation is required in order to draw conclusions in these areas. Our results suggest that, in the global open ocean, barotropic tidal currents have little impact on the transport and accumulation of floating microplastic and can thus be neglected in simulations aimed at studying microplastic transport in the open ocean., Key Points Barotropic tidal currents have little impact on transport and accumulation of floating microplastic in the global open oceanSimulations of plastic dispersion in the open ocean do not need to take barotropic tides into accountA computationally efficient implementation for advecting virtual particles by tidal currents is provided

Plastic marine debris (PMD) affects spatial scales of life from microbes to whales. However, understanding interactions between plastic and microbes in the "Plastisphere"-the thin layer of life on the surface of PMD-has been technology-limited. Research into microbe-microbe and microbe-substrate interactions requires knowledge of community phylogenetic composition but also tools to visualize spatial distributions of intact microbial biofilm communities. We developed a CLASI-FISH (combinatorial labelling and spectral imaging - fluorescence in situ hybridization) method using confocal microscopy to study Plastisphere communities. We created a probe set consisting of three existing phylogenetic probes (targeting all Bacteria, Alpha-, and Gammaproteobacteria) and four newly designed probes (targeting Bacteroidetes, Vibrionaceae, Rhodobacteraceae and Alteromonadaceae) labelled with a total of seven fluorophores and validated this probe set using pure cultures. Our nested probe set strategy increases confidence in taxonomic identification because targets are confirmed with two or more probes, reducing false positives. We simultaneously identified and visualized these taxa and their spatial distribution within the microbial biofilms on polyethylene samples in colonization time series experiments in coastal environments from three different biogeographical regions. Comparing the relative abundance of 16S rRNA gene amplicon sequencing data with cell-count abundance data retrieved from the microscope images of the same samples showed a good agreement in bacterial composition. Microbial communities were heterogeneous, with direct spatial relationships between bacteria, cyanobacteria and eukaryotes such as diatoms but also micro-metazoa. Our research provides a valuable resource to investigate biofilm development, succession and associations between specific microscopic taxa at micrometre scales.

Plastic debris has become an abundant pollutant in marine, coastal and riverine environments, posing a large threat to aquatic life. Effective measures to mitigate and prevent marine plastic pollution require a thorough understanding of its origin and eventual fate. Several models have estimated that land-based sources are the main source of marine plastic pollution, although field data to substantiate these estimates remain limited. Current methodologies to measure riverine plastic transport require the availability of infrastructure and accessible riverbanks, but, to obtain measurements on a higher spatial and temporal scale, new monitoring methods are required. This paper presents a new methodology for quantifying riverine plastic debris using Unmanned Aerial Vehicles (UAVs), including a first application on Klang River, Malaysia. Additional plastic measurements were done in parallel with the UAV-based approach to make comparisons between the two methods. The spatiotemporal distribution of the plastics obtained with both methods show similar patterns and variations. With this, we show that UAV-based monitoring methods are a promising alternative for currently available approaches for monitoring riverine plastic transport, especially in remote and inaccessible areas.

Captain Charles Moore introduced the world to the "Great Pacific Garbage Patch" in the mid-1990s. Since then, there has been increasing interest from scientists, the public and policy makers regarding plastic debris in the environment. A focus article in the July issue of the Society of Environmental Toxicology and Chemistry's journal, Environmental Toxicology and Chemistry, outlines the current research, identifies research gaps on plastic debris and reviews some of the weight of evidence regarding contamination, fate and effects of the material

As plastic waste accumulates in the ocean at alarming rates, the need for efficient and sustainable remediation solutions is urgent. One solution is the development and mobilization of technologies that either 1) prevent plastics from entering waterways or 2) collect marine and riverine plastic pollution. To date, however, few reports have focused on these technologies, and information on various technological developments is scattered. This leaves policymakers, innovators, and researchers without a central, comprehensive, and reliable source of information on the status of available technology to target this global problem. The goal of this study was to address this gap by creating a comprehensive inventory of technologies currently used or in development to prevent the leakage of plastic pollution or collect existing plastic pollution. Our Plastic Pollution Prevention and Collection Technology Inventory (https://nicholasinstitute.duke.edu/plastics-technology-inventory) can be used as a roadmap for researchers and governments to 1) facilitate comparisons between the scope of solutions and the breadth and severity of the plastic pollution problem and 2) assist in identifying strengths and weaknesses of current technological approaches. We created this inventory from a systematic search and review of resources that identified technologies. Technologies were organized by the type of technology and target plastics (i.e., macroplastics, microplastic, or both). We identified 52 technologies that fall into the two categories of prevention or collection of plastic pollution. Of these, 59% focus specifically on collecting macroplastic waste already in waterways. While these efforts to collect plastic pollution are laudable, their current capacity and widespread implementation are limited in comparison to their potential and the vast extent of the plastic pollution problem. Similarly, few technologies attempt to prevent plastic pollution leakage, and those that do are limited in scope. A comprehensive approach is needed that combines technology, policymaking, and advocacy to prevent further plastic pollution and the subsequent damage to aquatic ecosystems and human health.

Marine plastic debris can act as a reservoir of chemical additives that can pose a potential threat to sensitive ecosystems such as coral reefs. A survey of foam macrodebris collected on beaches indeed revealed high concentrations of hexabromocyclododecanes (ΣHBCDD) in polystyrene (PS) samples (up to 1940 μg g−1). Results also showed that PS fragments can still leach over 150 ng g−1 d−1 of ΣHBCDD (primarily as the α-isomer) for relatively long durations, and that these additives are readily bioaccumulated and well-retained by corals. Despite significant HBCDD bioaccumulation in coral tissue, short-term exposure to HBCDD or PS leachate had no considerable effect on coral photosynthetic activity, symbiont concentration and chlorophyll content. Exposure to the PS leachate did however cause consistent polyp retraction in nubbins over the 5-day exposure. This response was not observed in animals exposed to HBCDD alone, suggesting that another constituent of the leachate stressed corals.

Despite concerns regarding the environmental impacts of microplastics, knowledge of the incidence and levels of synthetic particles in large marine vertebrates is lacking. Here, we utilize an optimized enzymatic digestion methodology, previously developed for zooplankton, to explore whether synthetic particles could be isolated from marine turtle ingesta. We report the presence of synthetic particles in every turtle subjected to investigation (n = 102) which included individuals from all seven species of marine turtle, sampled from three ocean basins (Atlantic [ATL]: n = 30, four species; Mediterranean (MED): n = 56, two species; Pacific (PAC): n = 16, five species). Most particles (n = 811) were fibres (ATL: 77.1% MED: 85.3% PAC: 64.8%) with blue and black being the dominant colours. In lesser quantities were fragments (ATL: 22.9%: MED: 14.7% PAC: 20.2%) and microbeads (4.8%; PAC only; to our knowledge the first isolation of microbeads from marine megavertebrates). Fourier transform infrared spectroscopy (FT‐IR) of a subsample of particles (n = 169) showed a range of synthetic materials such as elastomers (MED: 61.2%; PAC: 3.4%), thermoplastics (ATL: 36.8%: MED: 20.7% PAC: 27.7%) and synthetic regenerated cellulosic fibres (SRCF; ATL: 63.2%: MED: 5.8% PAC: 68.9%). Synthetic particles being isolated from species occupying different trophic levels suggest the possibility of multiple ingestion pathways. These include exposure from polluted seawater and sediments and/or additional trophic transfer from contaminated prey/forage items. We assess the likelihood that microplastic ingestion presents a significant conservation problem at current levels compared to other anthropogenic threats., Knowledge of the incidence and levels of synthetic particles in large marine vertebrates is lacking. Here, we explore whether synthetic particles could be isolated from marine turtle ingesta and report the presence in every turtle subjected to investigation including individuals from all the seven species of marine turtle, sampled from three ocean basins. Most particles were fibres in lesser quantities were fragments/microbeads and were a range of synthetic materials. Synthetic particles isolated from species occupying different trophic levels suggest the possibility of multiple ingestion pathways. We assess the likelihood this presents a significant conservation problem at current levels.

The leakage of large plastic litter (macroplastics) into the ocean is a major environmental problem. A significant fraction of this leakage originates from coastal cities, particularly during extreme rainfall events. As coastal cities continue to grow, finding ways to reduce this macroplastic leakage is extremely pertinent. Here, we explore why and how coastal cities can reduce macroplastic leakages during extreme rainfall events. Using nine global cities as a basis, we establish that while cities actively create policies that reduce plastic leakages, more needs to be done. Nonetheless, these policies are economically, socially and environmentally cobeneficial to the city environment. While the lack of political engagement and economic concerns limit these policies, lacking social motivation and engagement is the largest limitation towards implementing policy. We recommend cities to incentivize citizen and municipal engagement with responsible usage of plastics, cleaning the environment and preparing for future extreme rainfall events.

Captain Charles Moore introduced the world to the "Great Pacific Garbage Patch" in the mid-1990s. Since then, there has been increasing interest from scientists, the public and policy makers regarding plastic debris in the environment. A focus article in the July issue of the Society of Environmental Toxicology and Chemistry's journal, Environmental Toxicology and Chemistry, outlines the current research, identifies research gaps on plastic debris and reviews some of the weight of evidence regarding contamination, fate and effects of the material

Marine plastics have shown to contain various environmental chemicals. For evaluating the potential of plastics to influence regional and global dynamics of these chemicals and to serve as a vector to marine biota, understanding of sorption and desorption of chemicals by plastics is important. In this chapter, the equilibrium sorption of neutral organic chemicals from water to plastics is discussed. First, the basic principles of equilibrium sorption are explained, and then, factors that influence the magnitude of the sorption coefficient, such as types of plastics and chemicals, temperature, coexisting organic and inorganic constituents in water, are overviewed. Successively, effects on the equilibrium sorption properties of field-relevant mechanisms such as degradation and biofouling as well as nano-sized plastics are discussed. It is evident that studies on sorption properties of aged plastics in field conditions are far less available than those of intact plastics in laboratory conditions.

Microplastics are small piece of plastic debris < 5 mm in diameter, which arise and enter the environment either as a consequence of the direct release of small pieces of plastic debris or as a consequence of the fragmentation of larger items. They are widely distributed in the marine environment, on shorelines, at the sea surface, on the seabed. They are also ingested by a variety of marine organisms, and there is some evidence that this may cause adverse effects. This thesis investigates the potential sources, distribution and fate of this contaminant. Deterioration of plastics in a variety of environments was examined as a potential source of microplastics. Plastics were exposed in light and shade, in air, fresh water and sea water. Their deterioration was monitored over six hundred days. The fastest rate of deterioration, by far, was observed in air, and this was further accelerated by natural sunlight. Degradation in water was much slower and it was therefore concluded that plastic debris only fragments slowly into microplastics while they are in the water, and much faster when they are washed ashore and/or remain exposed to air, for example on a beach. A method to assess the contamination of beaches by microplastics' likely predecessors - small items of plastic debris - was therefore developed. High spatial variability, which can impede comparison between surveys undertaken by random sampling was overcome by assessing deliberately selected debris accumulations. An attempt to utilise citizen science using this rapid survey approach returned too much variability between volunteers to obtain consistent results. Nevertheless, the survey method was successfully used to identify narrow opening towards the sea, small tidal range and several weeks of high on-beach waves as predictors for high contamination. Evidence of harmful effects of microplastics on animals is primarily from laboratory studies and could be substantiated by exposure experiments \emph{in-situ}. Cockles were exposed to fluorescent plastic particles in an intertidal mudflat. After two weeks, particles were still present in the sediment. However, the test material could not be identified in the cockles with enough certainty to validate the method. The thesis concludes that fragmentation of larger items of debris on land is an important potential source of microplastics. Therefore, preventing plastics that are prone to deteriorate from entering the environment is likely the most effective way to prevent the generation of microplastics. Measuring the success of such preventive measures in the field returns highly variable results, as small plastic debris are elusive. Measuring effects in the environment demands large amounts of data, and highly specific methods are required to detect microplastics in animals. The shift of environmental plastic contamination towards small particles demands that plastic debris research adjusts to the elusiveness of these particles. Large volumes of variable data on plastics density and precise biological essays will be required.

Som en del av denne studien har det ved en litteraturstudie blitt forsøkt å belyse dagens kunnskapsstatus rundt marin plast i norske kyst- og havområder. Det viser seg at 80-90 % av marint avfall som avsettes langs Norges strender består av plast. Det har samtidig blitt observert økende mengder plastavfall avsatt langs Norges strender fra 2011-2013. Mengde og sammensetning av plast, som inntas av havhester (Fulmarus glacialis) reflekterer situasjonen rundt marint plastavfall til havs. I perioden 2005-2009 hadde 52% av havhester innhentet fra Lista i Vest-Agder mer enn 0,1 gram plast i magen, noe som er 3% nedgang fra perioden 2002-2006. Det observeres ingen klar trend i plastmengder fra havhesten ved Lista, men er derimot økende for sørvestlige deler av Nordsjøen. Det observeres samtidig at havhester inntar mindre plast i nordligere havområder, som er grunnet avtagende mengder marint plastavfall mot nordligere havområder. Nok et mål for denne studien var å forsøke å finne en korrelasjon mellom konsentrasjoner av persistente organiske miljøgifter (POPs) adsorbert til inntatt plast fra havhester, og POPs- konsentrasjoner detektert i havhestenes levere. Inntatt plast, lever- og muskelvev fra åtte havhester innsamlet fra Nord-Troms og Vest- Finnmark i 2012 ble analysert for organiske persistente miljøgifter (POPs), som polyklorerte bifenyler (PCB), typiske klorerte pesticider og polybromerte difenyletere (PBDE). Alle havhestene hadde plast i magen i ulik grad, alt bestående av brukerplast, der 37,5% av havhestene hadde inntatt mer enn 0,1 gram plast. Ingen korrelasjon kunne påvises mellom PCB-konsentrasjoner i plast inntatt av havhestene og PCB-konsentrasjoner akkumulert i havhestenes levre. Det ble heller ikke funnet noen slik korrelasjon for de fleste klorerte pesticider, bortsett fra heksaklorbenzen (HCB). HCB- konsentrasjoner som ble funnet i levrene til havhestene korrelerte med HCB-konsentrasjoner i den inntatte plasten fra havhestene (R2=0,61441, P=0,0213). En korrelasjon mellom PBDE-konsentrasjoner i inntatt plast fra havhest og PBDE- konsentrasjoner i havhestens levre, kunne påvises, da PBDE (BDE-47) kun ble detektert over deteksjonsgrensen i plast fra to av åtte havhester. Videre ble det verken observert noen korrelasjon mellom antall inntatte plastbiter fra havhestene og POPs-konsentrasjoner i havhestenes levre, eller mellom vekten av den inntatte plasten og POPs-konsentrasjoner i havhestenes levre. As part of this study, literature has been reviewed to investigate the current status of knowledge on marine plastic debris in the surrounding waters of Norway and along the Norwegian coastline. It has been uncovered that 80-90% of all the marine debris that has been observed along the Norwegian coastline consists of plastic. The amounts of beached plastics collected seem to have increased from 2011-2013. The situation regarding plastic waste at sea is reflected by the amount and composition of plastics ingested by northern fulmars (Fulmasrus glacialis). In the period of 2005-2009, 52% of the northern fulmars collected at Lista in Vest-Agder had ingested more than 0,1 grams of plastics, which is 3% less than what was registered in the period 2002-2006. A trend in the amount of ingested plastics is not clear for Lista, but seems to be increasing in southwestern parts of the North Sea. In addition, plastic ingestion by northern fulmars tend to decrease towards high M-KB