The Arctic ecosystem receives contaminants transported through complex environmental pathways – such as atmospheric, riverine and oceanographic transport, as well as local infrastructure. A holistic ...approach is required to assess the impact that plastic pollution may have on the Arctic, especially with regard to the unseen microplastics. This study presents data on microplastics in the Arctic fjords of western Svalbard, by addressing the ecological consequences of their presence in coastal surface waters and sediment, and through non-invasive approaches by sampling faeces from an apex predator, the benthic feeder walrus (Odobenus rosmarus). Sample locations were chosen to represent coastal areas with different degrees of anthropogenic pollution and geographical features (e.g., varying glacial coverage of catchment area, winter ice cover, traffic, visitors), while also relevant feeding grounds for walrus. Microplastics in surface water and sediments ranged between <LOD (limit of detection)-3.5 particles/m3 and <LOD-26 particles/kg dry weight, respectively. This study shows that microplastics may also enter the Arctic food web as the microplastic concentration in walrus faeces were estimated at an average of 34 particles/kg. Polyester was identified by Fourier transformation infrared spectroscopy (FT-IR) as the most common plastic polymer (58% in water, 31% in walrus), while fibres were the most common shape (65% water, 71% in sediment, 70% walrus). There was no significant difference in microplastic occurrence between water samples from populated or remote fjords, suggesting that microplastics are a ubiquitous contaminant which is available for interaction with Arctic marine animals even at distances from settlements. The present study contributes to our understanding of microplastics in the remote Arctic ecosystem. It also identifies the potential of non-invasive sampling methods for investigating Arctic pinnipeds. This approach will need further development and standardisation before utilisation to monitor plastic pollution in other marine mammals.
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•Water samples showed no difference in microplastic concentration between fjords.•Sediment particle concentration revealed similar levels to other Arctic studies.•No difference in particle concentrations between populated and remote Svalbard fjords•Non-invasive method to investigate interaction of marine mammals with microplastics•First observation of microplastics in walrus faeces averaging 34 particles/kg
Buried microplastics (plastics, <5 mm) have been documented within the sediment column of both marine and lacustrine environments. However, the number of peer-review studies published on the subject ...remains limited and confidence in data reliability varies considerably. Here we critically review the state of the literature on microplastic loading inventories in dated sedimentary and soil profiles. We conclude that microplastics are being sequestered across a variety of sedimentary environments globally, at a seemingly increasing rate. However, microplastics are also readily mobilised both within depositional settings and the workplace. Microplastics are commonly reported from sediments dated to before the onset of plastic production and researcher-derived microplastics frequently contaminate samples. Additionally, the diversity of microplastic types and issues of constraining source points has so far hindered interpretation of depositional settings. Therefore, further research utilizing high quality data sets, greater levels of reporting transparency, and well-established methodologies from the geosciences will be required for any validation of microplastics as a sediment dating method or in quantifying temporally resolved microplastic loading inventories in sedimentary sinks with confidence.
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•Field studies investigating microplastics in natural archives are scarce.•Data quality issues are prevalent in microplastic sedimentation publications.•The microplastic emissions' record in sediments is often incomplete.•Microplastics as time-synchronous marker horizons require further validation.
Microplastic presence in benthic marine systems is a widely discussed topic. The influence of the natural matrix on microplastic distribution within the sedimentary matrix is often overlooked. Marine ...sediments from the western inner Oslofjord, Norway, were investigated for temporal trends, with a particular focus on the relationship between sediment grain-sizes and microplastic distribution. Density separation, optical microscopy and chemical validation were used to categorize microplastics. Microplastic concentrations ranged from 0.02 to 1.71 MPs g −1 dry weight (dw). Fibres were the most common (76%), followed by fragments and films (18%, 6%). Common polymers were polyesters (50%), polypropylene (18%), polymethylmethacrylate (9%), rayon and viscose (5%) and elastane (4%). Microplastics appear to accumulate preferentially according to their morphology and polymer type in certain sediment grain-sizes. Microplastics inputs to the Oslofjord appear to derive from a wastewater treatment plant in the vicinity. Although, the redistribution of microplastics within the fjord needs further investigation.
•Microplastics were detected in marine sediments of the western inner Oslofjord.•The distribution of microplastics in sediments was statistically analysed.•Considerations were made on the release of microplastics from a WWTP.•Microplastics can be redistributed in the fjord by shallow and deep currents.•The occurrence of microplastics in sediments could affect benthic fauna.
The ubiquity and high bioavailability of microplastics have an unknown risk on the marine environment. Biomonitoring should be used to investigate biotic impacts of microplastic exposure. While many ...studies have used mussels as indicators for marine microplastic pollution, a robust and clear justification for their selection as indicator species is still lacking. Here, we review published literature from field investigations and laboratory experiments on microplastics in mussels and critically discuss the suitability and challenges of mussels as bioindicator for microplastic pollution. Mussels are suitable bioindicator for microplastic pollution because of their wide distribution, vital ecological niches, susceptibility to microplastic uptake and close connection with marine predators and human health. Field investigations highlight a wide occurrence of microplastics in mussels from all over the world, yet their abundance varies enormously. Problematically, these studies are not comparable due to the lack of a standardized approach, as well as temporal and spatial variability. Interestingly, microplastic abundance in field-collected mussels is closely related to human activity, and there is evidence for a positive and quantitative correlation between microplastics in mussels and surrounding waters. Laboratory studies collectively demonstrate that mussels may be good model organisms in revealing microplastic uptake, accumulation and toxicity. Consequently, we propose the use of mussels as target species to monitor microplastics and call for a uniform, efficient and economical approach that is suitable for a future large-scale monitoring program.
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•Microplastics have been investigated and found in mussels around the world.•Mussel can be a good organism to study the toxicity of microplastic in the laboratory.•Mussel is proposed as a global bioindicator of microplastic pollution.•It is necessary to develop a uniform protocol for microplastic monitoring in mussels.
Mussel is a global bioindicator of microplastic pollution.
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•Microplastics have been analyzed widely in the Norwegian environment.•Multi-actor discussions in Norway identified several persistent knowledge gaps.•Validation and harmonization of ...analytical methods are needed to advance research.•Elucidating drivers and mechanisms of microplastic toxicity is still a challenge.•Complex ecological interactions inspire adopting a precautionary approach.•Multi-actor communication is essential to define and facilitate strategic research.
Given the increasing attention on the occurrence of microplastics in the environment, and the potential environmental threats they pose, there is a need for researchers to move quickly from basic understanding to applied science that supports decision makers in finding feasible mitigation measures and solutions. At the same time, they must provide sufficient, accurate and clear information to the media, public and other relevant groups (e.g., NGOs). Key requirements include systematic and coordinated research efforts to enable evidence-based decision making and to develop efficient policy measures on all scales (national, regional and global). To achieve this, collaboration between key actors is essential and should include researchers from multiple disciplines, policymakers, authorities, civil and industry organizations, and the public. This further requires clear and informative communication processes, and open and continuous dialogues between all actors. Cross-discipline dialogues between researchers should focus on scientific quality and harmonization, defining and accurately communicating the state of knowledge, and prioritization of topics that are critical for both research and policy, with the common goal to establish and update action plans for holistic benefit. In Norway, cross-sectoral collaboration has been fundamental in supporting the national strategy to address plastic pollution. Researchers, stakeholders and the environmental authorities have come together to exchange knowledge, identify knowledge gaps, and set targeted and feasible measures to tackle one of the most challenging aspects of plastic pollution: microplastic. In this article, we present a Norwegian perspective on the state of knowledge on microplastic research efforts. Norway’s involvement in international efforts to combat plastic pollution aims at serving as an example of how key actors can collaborate synergistically to share knowledge, address shortcomings, and outline ways forward to address environmental challenges.
Microplastics are a diverse category of pollutants, comprising a range of constituent polymers modified by varying quantities of additives and sorbed pollutants, and exhibiting a range of ...morphologies, sizes, and visual properties. This diversity, as well as their microscopic size range, presents numerous barriers to identification and enumeration. These issues are addressed with the application of physical and chemical analytical procedures; however, these present new problems associated with researcher training, facility availability and cost, especially for large-scale monitoring programs. Perhaps more importantly, the classifications and nomenclature used by individual researchers to describe microplastics remains inconsistent. In addition to reducing comparability between studies, this limits the conclusions that may be drawn regarding plastic sources and potential environmental impacts. Additionally, where particle morphology data is presented, it is often separate from information on polymer distribution. In establishing a more rigorous and standardized visual identification procedure, it is possible to improve the targeting of complex analytical techniques and improve the standards by which we monitor and record microplastic contamination. Here we present a simple and effective protocol to enable consistent visual processing of samples with an aim to contribute to a higher degree of standardization within the microplastic scientific community. This protocol will not eliminate the need for non-subjective methods to verify plastic objects, but it will standardize the criteria by which suspected plastic items are identified and reduce the costs associated with further analysis.
Comparative investigations of microplastic (MP) occurrence in the global ocean are often hampered by the application of different methods. In this study, the same sampling and analytical approach was ...applied during five different cruises to investigate MP covering a route from the East-Siberian Sea in the Arctic, through the Atlantic, and into the Antarctic Peninsula. A total of 121 subsurface water samples were collected using underway pump-through system on two different vessels. This approach allowed subsurface MP (100 μm–5 mm) to be evaluated in five regions of the World Ocean (Antarctic, Central Atlantic, North Atlantic, Barents Sea and Siberian Arctic) and to assess regional differences in MP characteristics. The average abundance of MP for whole studied area was 0.7 ± 0.6 items/m3 (ranging from 0 to 2.6 items/m3), with an equal average abundance for both fragments and fibers (0.34 items/m3). Although no statistical difference was found for MP abundance between the studied regions. Differences were found between the size, morphology, polymer types and weight concentrations. The Central Atlantic and Barents Sea appeared to have more MP in terms of weight concentration (7–7.5 μg/m3) than the North Atlantic and Siberian Arctic (0.6 μg/m3). A comparison of MP characteristics between the two Hemispheres appears to indicate that MP in the Northern Hemisphere mostly originate from terrestrial input, while offshore industries play an important role as a source of MP in the Southern Hemisphere. The waters of the Northern Hemisphere were found to be more polluted by fibers than those of the Southern Hemisphere. The results presented here suggest that fibers can be transported by air and water over long distances from the source, while distribution of fragments is limited mainly to the water mass where the source is located.
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•Microplastics (MPs) were found in all studied Ocean regions.•MPs abundance is similar in the studied regions; weight concentration is different.•The Northern Hemisphere is more fiber-polluted than the Southern Hemisphere.•Fibers abundance depends on distance from shore and latitude.
Plastic is a ubiquitous contaminant of the Anthropocene. The highly diverse nature of microplastic pollution means it is not a single contaminant, but a suite of chemicals that include a range of ...polymers, particle sizes, colors, morphologies, and associated contaminants. Microplastics research has rapidly expanded in recent years and has led to an overwhelming consideration in the peer-reviewed literature. While there have been multiple calls for standardization and harmonization of the research methods used to study microplastics in the environment, the complexities of this emerging field have led to an exploration of many methods and tools. While different research questions require different methods, making standardization often impractical, it remains import to harmonize the outputs of these various methodologies. We argue here that in addition to harmonized methods and quality assurance practices, journals, editors and reviewers must also be more proactive in ensuring that scientific papers have clear, repeatable methods, and contribute to a constructive and factual discourse on plastic pollution. This includes carefully considering the quality of the manuscript submissions and how they fit into the larger field of research. While comparability and reproducibility is critical in all fields, we argue that this is of utmost importance in microplastics research as policy around plastic pollution is being developed in real time alongside this evolving scientific field, necessitating the need for rigorous examination of the science being published.
An interlaboratory comparison exercise was conducted to assess the consistency of microplastic quantification across several laboratories. The test samples were prepared by mixing one liter seawater ...free of plastics, microplastics made from polypropylene, high- and low-density polyethylene, and artificial particles in two plastic bottles, and analyzed concurrently in 12 experienced laboratories around the world. The minimum requirements to quantify microplastics were examined by comparing actual numbers of microplastics in these sample bottles with numbers measured in each laboratory. The uncertainty was due to pervasive errors derived from inaccuracies in measuring sizes and/or misidentification of microplastics, including both false recognition and overlooking. The size distribution of microplastics should be smoothed using a running mean with a length of >0.5 mm to reduce uncertainty to less than ±20%. The number of microplastics <1 mm was underestimated by 20% even when using the best practice for measuring microplastics in laboratories.
•An interlaboratory comparison exercise was conducted across 12 laboratories.•Samples were prepared by mixing seawater, man-made microplastics, and particles.•The minimum requirements to quantify microplastics were examined.•The number of microplastics <1 mm was underestimated by 20%.
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