Microplastics contaminate the deepest part of the world’s ocean

Millions of metric tons of plastics are produced annually and transported from land to the oceans. Finding the fate of the plastic debris will help define the impacts of plastic pollution in the ocean. Here, we report the abundances of microplastic in the deepest part of the world’s ocean. We found that microplastic abundances in hadal bottom waters range from 2.06 to 13.51 pieces per litre, several times higher than those in open ocean subsurface water. Moreover, microplastic abundances in hadal sediments of the Mariana Trench vary from 200 to 2200 pieces per litre, distinctly higher than those in most deep sea sediments. These results suggest that manmade plastics have contaminated the most remote and deepest places on the planet. The hadal zone is likely one of the largest sinks for microplastic debris on Earth, with unknown but potentially damaging impacts on this fragile ecosystem.

X. Peng, M. Chen, S. Chen and al., Geochemical Perspectives Letters v9, Published 27 November 2018

The article

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Double trouble in the South Pacific subtropical gyre: Increased plastic ingestion by fish in the oceanic accumulation zone

Fish are an important food source for South Pacific (SP) island countries, yet there is little information on contamination of commercial marine fish species by plastic. The aim of our study was to perform a broad-scale assessment of plastic ingestion by fish common in the diet of SP inhabitants. We examined 932 specimens from 34 commercial fish species across four SP locations, and some of the prey they ingested, for the presence of marine plastics. Plastic was found in 33 species, with an average ingestion rate (IR) of 24.3 ± 1.4% and plastic load of 2.4 ± 0.2 particles per fish. Rapa Nui fish exhibited the greatest IR (50.0%), significantly greater than in other three locations. Rapa Nui is located within the SP subtropical gyre, where the concentration of marine plastics is high and food is limited. Plastic was also found in prey, which confirms the trophic transfer of microplastics.

A. Markic, C. Niemand, J. H. Bridson and al., Marine Pollution Bulletin, Volume 136, November 2018, Pages 547-564

The article

Effects of polymethylmethacrylate nanoplastics on Dicentrarchus labrax

The present study aimed to evaluate the effects of ~45 nm nanoplastics (NPs) on the marine fish Dicentrarchus labrax after a short-term exposure. Animals were exposed to a concentration range of NPs for 96 h and liver, plasma and skin mucus were sampled. Assessed endpoints included biochemical biomarkers and expression of genes related to lipid metabolism, immune system and general cell stress. Abundance of mRNA transcripts related to lipid metabolism, pparα and pparγ, were significantly increased after exposure to NPs. Biochemical endpoints revealed decreased esterase activity levels in plasma, suggesting that the immune system of fish might be compromised by exposure to NPs. Moreover, significantly lower levels of alkaline phosphatase were found in the skin mucus of animals exposed to NPs. The present results suggest that NPs may represent a hazard to this marine fish, potentially interfering with the metabolism of lipids and the correct function of the immune response.

I. Brandts, M. Teles, A. Tvarijonaviciute and al., Genomics, Volume 110, Issue 6, November 2018, Pages 435-441

The article

Low prevalence of microplastic contamination in planktivorous fish species from the southeast Pacific Ocean

The gut contents of 292 planktivorous fish, from four families (Atherinopsidae, Clupeidae, Engraulidae and Scombridae) and seven species, captured along the coast of the southeast Pacific, were examined for microplastic contamination. Only a small fraction of all studied fish (2.1%; 6 individuals) contained microplastic particles in their digestive tract. Microplastics found were degraded hard fragments and threads, ranging from 1.1 to 4.9 (3.8 ± SD 2.4) mm in length, and of various colours, which suggests that the planktivorous fish species examined herein did not capture microplastics on the basis of their colour. The low prevalence of microplastic contamination in planktivorous fishes found in this study suggests that the risk of accidental ingestion by these species might be limited in the coastal upwelled waters of the southeast Pacific, perhaps due to small human population and highly dynamic oceanographic processes.

N. Ory, C. Chagnon, F. Felix and al., Marine Pollution Bulletin, Volume 127, February 2018, Pages 211-216

Identification and quantitation of semi-crystalline microplastics using image analysis and differential scanning calorimetry

There are several techniques used to analyze microplastics. These are often based on a combination of visual and spectroscopic techniques. Here we introduce an alternative workflow for identification and mass quantitation through a combination of optical microscopy with image analysis (IA) and differential scanning calorimetry (DSC). We studied four synthetic polymers with environmental concern: low and high density polyethylene (LDPE and HDPE, respectively), polypropylene (PP), and polyethylene terephthalate (PET). Selected experiments were conducted to investigate (i) particle characterization and counting procedures based on image analysis with open-source software, (ii) chemical identification of microplastics based on DSC signal processing, (iii) dependence of particle size on DSC signal, and (iv) quantitation of microplastics mass based on DSC signal. We describe the potential and limitations of these techniques to increase reliability for microplastic analysis. Particle size demonstrated to have particular incidence in the qualitative and quantitative performance of DSC signals. Both, identification (based on characteristic onset temperature) and mass quantitation (based on heat flow) showed to be affected by particle size. As a result, a proper sample treatment which includes sieving of suspended particles is particularly required for this analytical approach.

Mauricio Rodríguez Chialanza, Ignacio Sierra, Andrés Pérez Parada, Laura Fornaro, Environmental Science and Pollution Research, pp 1–9, April 2018

Plastic pollution in islands of the Atlantic Ocean

Marine plastic pollution is present in all oceans, including remote oceanic islands. Despite the increasing number of articles on plastic pollution in the last years, there is still a lack of studies in islands, that are biodiversity hotspots when compared to the surrounding ocean, and even other recognized highly biodiverse marine environments. Articles published in the peer reviewed literature (N = 20) were analysed according to the presence of macro (>5 mm) and microplastics (<5 mm) on beaches and the marine habitats immediately adjacent to 31 islands of the Atlantic Ocean and Caribbean Sea. The first articles date from the 1980s, but most were published in the 2000s. Articles on macroplastics were predominant in this review (N = 12). Beaches were the most studied environment, possibly due to easy access. The main focus of most articles was the spatial distribution of plastics associated with variables such as position of the beach in relation to wind and currents. Very few studies have analysed plastics colonization by organisms or the identification of persistent organic pollutants (POPs). Islands of the North/South Atlantic and Caribbean Sea were influenced by different sources of macroplastics, being marine-based sources (i.e., fishing activities) predominant in the Atlantic Ocean basin. On the other hand, in the Caribbean Sea, land-based sources were more common.

Raqueline C. P. Monteiro, Juliana A. Ivar do Sul, Monica F. Costa, Environmental Pollution, Volume 238, July 2018, Pages 103–110

The article

Microplastics in Polar Regions: the role of long range transport

Microplastics (particles <5 mm) pose a threat to the marine ecosystem that is disproportionate to their tiny size. They have been found in high numbers in sea water and sediments, and are interacting with organisms and the environment in a variety of ways. Recently their presence has been confirmed in Polar water, sediment, and sea ice. We review the recent literature on microplastic distribution and transport in marine environments, primarily in the Northern Hemisphere, summarize current understanding, identify gaps in understanding, and suggest future research priorities.

Rachel W. Obbard, Current Opinion in Environmental Science & Health, Available online 13 December 2017, In Press