Microplastics in marine sediments near Rothera Research Station, Antarctica

Antarctica and surrounding waters are often considered pristine, but may be subject to local pollution from tourism, fishing and governmental research programme activities. In particular, the quantification of microplastic pollution within the Antarctic Treaty area (south of latitude 60°S) has received little attention. We examined microplastic particle concentrations in sediment samples from 20 locations up to 7 km from Rothera Research Station. The highest concentrations of microplastic (<5 particles 10 ml−1) were recorded in sediment collected near the station sewage treatment plant outfall. The concentrations were similar to levels recorded in shallow and deep sea marine sediments outside Antarctica. The detected microplastics had characteristics similar to those commonly produced by clothes washing. We recommend further research on microplastics around Antarctic stations to inform policy discussions and the development of appropriate management responses.

Sarah Reed, Marlon Clark, Richard Thompson, Kevin A. Hughes, Marine Pollution Bulletin, Volume 133, August 2018, Pages 460–463

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Identification of microplastics using Raman spectroscopy: Latest developments and future prospects

Widespread microplastic pollution is raising growing concerns as to its detrimental effects upon living organisms. A realistic risk assessment must stand on representative data on the abundance, size distribution and chemical composition of microplastics. Raman microscopy is an indispensable tool for the analysis of very small microplastics (<20 μm). Still, its use is far from widespread, in part due to drawbacks such as long measurement time and proneness to spectral distortion induced by fluorescence. This review discusses each drawback followed by a showcase of interesting and easily available solutions that contribute to faster and better identification of microplastics using Raman spectroscopy. Among discussed topics are: enhanced signal quality with better detectors and spectrum processing; automated particle selection for faster Raman mapping; comprehensive reference libraries for successful spectral matching. A last section introduces non-conventional Raman techniques (non-linear Raman, hyperspectral imaging, standoff Raman) which permit more advanced applications such as real-time Raman detection and imaging of microplastics.

Catarina F. Araujo, Mariela M. Nolasco, Antonio M.P. Ribeiro, Paulo J.A. Ribeiro-Claro, Water Research, Volume 142, 1 October 2018, Pages 426-440

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Microplastic pollution in North Yellow Sea, China: Observations on occurrence, distribution and identification

Microplastics are emerging contaminants and have attracted widespread environmental concerns about their negative effects on the marine ecosystems. In this study, we investigated the abundances, distributions and characteristics of microplastics in surface seawater and sediments from the North Yellow Sea. The results showed that the abundance of microplastics was 545 ± 282 items/m3 in surface seawater and 37.1 ± 42.7 items/kg dry weight in sediments, representing a medium microplastic pollution level compared with other sea areas. Small microplastics (<1 mm) made up >70% of the total microplastic numbers. Films and fibers were the dominant shapes of microplastics in both the surface seawater and sediments. Transparent microplastics were generally more common than microplastics of other colors. Based on the identification by a Fourier transform infrared microscope, polyethylene (PE) was the dominant composition of microplastics in surface seawater, while polypropylene (PP) was the most common polymer type in sediments. These results will improve our understanding of the environmental risks posed by microplastics to marine ecosystems.

Lin Zhu, Huaiyu Bai, Bijuan Chen and al., Science of The Total Environment, Volume 636, 15 September 2018, Pages 20-29

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Microplastics and polycyclic aromatic hydrocarbons (PAHs) in Xiamen coastal areas: Implications for anthropogenic impacts

Microplastics and polycyclic aromatic hydrocarbons (PAHs) were investigated to study the influence of human activities and to find their possible relationship on the coastal environments, where the coastal areas around Xiamen are undergoing intensive processes of industrialization and urbanization in the southeast China. The abundance of microplastics in Xiamen coastal areas was 103 to 2017 particles/m3 in surface seawater and 76 to 333 particles/kg in sediments. Concentrations of dissolved PAHs varied from 18.1 to 248 ng/L in surface seawater. The abundances of microplastics from the Western Harbor in surface seawater and sediments were higher than those from other areas. Foams were dominated in surface seawater samples, however, no foams were found in sediments samples. The microscope selection and FTIR analysis suggested that polyethylene (PE) and polypropylene (PP) were dominant microplastics. The cluster analysis results demonstrated that fibers and granules had the similar sources, and films had considerably correlation with all types of PAHs (3 or 4-ring PAHs and alkylated PAHs). Plastic film mulch from agriculture practice might be a potential source of microplastics in study areas. Results of our study support that river runoff, watershed area, population and urbanization rate influence the distribution of microplastics in estuarine surface water, and the prevalence of microplastic pollution calls for monitoring microplastics at a national scale.

G. Tang, M. Liu, Q. Zhou and al., Science of The Total Environment, Volume 634, 1 September 2018, Pages 811-820

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The hidden microplastics. New insights and figures from the thorough separation and characterization of microplastics and of their degradation by-products in coastal sediments

The environmental pollution by plastic debris directly dispersed in or eventually reaching marine habitats is raising increasing concern not only for the vulnerability of marine species to ingestion and entanglement by macroscopic debris, but also for the potential hazards from smaller fragments down to a few micrometer size, often referred to as “microplastics”. A novel procedure for the selective quantitative and qualitative determination of organic solvent soluble microplastics and microplastics degradation products (<2mm) in shoreline sediments was adopted to evaluate their concentration and distribution over the different sectors of a Tuscany (Italy) beach. Solvent extraction followed by gravimetric determination and chemical characterization by FT-IR, Pyrolysis-GC-MS, GPC and 1H-NMR analyses showed the presence of up to 30 mg microplastics in 1 kg sand, a figure corresponding to about 5.5 g of generally undetected and largely underestimated microplastics in the upper 10 cm layer of a square meter of sandy beach ! The extracted microplastic material was essentially polystyrene and polyolefin by-products from oxidative degradation and erosion of larger fragments, with accumulation mainly above the storm berm. Chain scission and oxidation processes cause significant variations in the physical and chemical features of microplastics, promoting their adsorption onto sand particles and thus their persistence in the sediments.

Alessio Ceccarini, Andrea Corti, Francesca Erba, Francesca Modugno, Jacopo La Nasa, Sabrina Bianchi, and Valter Castelvetro, Environ. Sci. Technol., Just Accepted Manuscript, April 23, 2018

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

Is the microplastic selective according to the habitat? Records in amphioxus sands, Mäerl bed habitats and Cymodocea nodosa habitats

This study estimated for the first time the total loads of plastic litter (macro- meso- and micro-plastics) in sediments of different habitat types from the Northern Adriatic Sea. Samples were collected in March 2016. The sampling sites were settled in shoreline, on the C. nodosa bottoms, Amphioxus sands, and Mäerl bed habitats. Microplastics items were present in all sampling site and ranging within 137-703 items/kg d.w. from Mäerl bed habitat to the shoreline. In C. nodosa bottoms 170 items/kg d.w. were found, while in Amphioxus sands were recorded on average 194 items/kg d.w. Due to the absence of statistical associations among litter levels and abundance of B. lanceolatum in the study area, this research present the needs to develop a new method and more research to for the evaluation of how much the interrelation between sensible habitats and microplastic exist.

M. Renzi, A. Blašković, P. Fastelli and al., Marine Pollution Bulletin, Volume 130, May 2018, Pages 179-183

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