Sea Water Contamination in the Vicinity of the Italian Minor Islands Caused by Microplastic Pollution

The abundance and distribution of microplastics (MP) were evaluated in six “clean” sites (Italian minor islands) and in two “polluted” areas (near the mouth of two major Italian rivers). Samples of MP, plankton and persistent organic pollutants (POPs) were collected using a manta trawl (MA) and a plankton net (WP2), both lined with a 333 µm mesh net. MP have been confirmed to be ubiquitous since they were found at each site, showing an average density of 0.3 ± 0.04 items/m3 (values ranged from 0.641 to 0.119 ). When comparing the clean sites with the polluted ones, a significantly higher value of MP was found near the river mouths. The most common types of MP were synthetic filaments (50.24%), followed by fragments (30.39%), thin plastic films (16.98%) and spheres (2.39%). Infrared spectroscopy analysis highlighted that the most abundant polymers were polyethylene (PE-26%), polypropylene (PP-11%), polyethylene-terephthalate/polyester (PET/PEST-8%) and ethylene-vinyl-acetate (EVA-5%). Polychlorinated biphenyls and organochlorine pesticides were detected in all the samples with a high variability among sites and depths. This study adds to the existing information on the distribution of contaminants across the Mediterranean Sea, and is useful to policy makers who wish to implement effective measures to reduce MP pollution.

Giuseppe Andrea de Lucia, Alvise Vianello, Andrea Camedda and al., Water, 2018, 10(8), 1108

The article

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Instrumental analysis of microplastics-benefits and challenges

There is a high demand for easy, cheap, comparable, and robust methods for microplastic (MP) analysis, due to the ever-increasing public and scientific interest in (micro-) plastic pollution in the environment. Today, a multitude of methodologies for sampling, sample preparation, and analysis of MPs are in use. This feature article deals with the most prominent detection methods as well as with sampling strategies and sample preparation techniques. Special emphasis is on their benefits and challenges. Thus, spectroscopic methods, coupled with microscopy, require time-consuming sample preparation and extended measurement times, whereas thermo-analytical methods are faster but lack the ability to determine the size distribution in samples. To that effect, most of the described methods are applicable depending on the defined analytical question.

Sven Huppertsberg, Thomas P. Knepper, Analytical and Bioanalytical Chemistry, , Volume 410, Issue 25, pp 6343–6352

The article

Optimization, performance, and application of a pyrolysis-GC/MS method for the identification of microplastics

Plastics are found to be major debris composing marine litter; microplastics (MP, < 5 mm) are found in all marine compartments. The amount of MPs tends to increase with decreasing size leading to a potential misidentification when only visual identification is performed. These last years, pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) has been used to get information on the composition of polymers with some applications on MP identification. The purpose of this work was to optimize and then validate a Py-GC/MS method, determine limit of detection (LOD) for eight common polymers, and apply this method on environmental MP. Optimization on multiple GC parameters was carried out using polyethylene (PE) and polystyrene (PS) microspheres. The optimized Py-GC/MS method require a pyrolysis temperature of 700 °C, a split ratio of 5 and 300 °C as injector temperature. Performance assessment was accomplished by performing repeatability and intermediate precision tests and calculating limit of detection (LOD) for common polymers. LODs were all below 1 μg. For performance assessment, identification remains accurate despite a decrease in signal over time. A comparison between identifications performed with Raman micro spectroscopy and with Py-GC/MS was assessed. Finally, the optimized method was applied to environmental samples, including plastics isolated from sea water surface, beach sediments, and organisms collected in the marine environment. The present method is complementary to μ-Raman spectroscopy as Py-GC/MS identified pigment containing particles as plastic. Moreover, some fibers and all particles from sediment and sea surface were identified as plastic.

Ludovic Hermabessiere, Charlotte Himber, Béatrice Boricaud, Maria Kazour, Rachid Amara, Anne-Laure Cassone, Michel Laurentie, Ika Paul-Pont, Philippe Soudant, Alexandre Dehaut, Guillaume Duflos, Analytical and Bioanalytical Chemistry, , Volume 410, Issue 25, pp 6663–6676

The article

Microplastic contamination in benthic organisms from the Arctic and sub-Arctic regions

The seafloor is recognized as one of the major sinks for microplastics (MPs). However, to date there have been no studies reported the MP contamination in benthic organisms from the Arctic and sub-Arctic regions. Therefore, this study provided the first data on the abundances and characteristics of MPs in a total of 413 dominant benthic organisms representing 11 different species inhabiting in the shelf of Bering and Chukchi Seas. The mean abundances of MP uptake by the benthos from all sites ranged from 0.02 to 0.46 items g−1 wet weight (ww) or 0.04–1.67 items individual−1, which were lower values than those found in other regions worldwide. The highest value appeared at the northernmost site, implying that the sea ice and the cold current represent possible transport mediums. Interestingly, the predator A. rubens ingested the maximum quantities of MPs, suggesting that the trophic transfer of MPs through benthic food webs may play a critical role. Fibers constituted the major type (87%) in each species, followed by film (13%). The colors of fibers were classified as red (46%) and transparent (41%), and the film was all gray. The predominant composition was polyamide (PA) (46%), followed by polyethylene (PE) (23%), polyester (PET) (18%) and cellophane (CP) (13%). The most common sizes of MPs concentrated in the interval from 0.10 to 1.50 mm, and the mean size was 1.45 ± 0.13 mm. Further studies about the temporal trends and detrimental effects of MPs remain to be carried out in benthic organisms from the Arctic and sub-Arctic regions.

Chao Fang, Ronghui Zheng, Yusheng Zhang and al., Chemosphere, Volume 209, October 2018, Pages 298–306

The article

Toxicities of polystyrene nano- and microplastics toward marine bacterium Halomonas alkaliphila

Nano- and microplastics have been shown to cause negative effects on marine organisms. However, the toxicities of nano- and microplastics toward marine bacteria are poorly understood. In this study, we investigated the toxic effects of polystyrene nano- and microplastics on the marine bacterium Halomonas alkaliphila by determining growth inhibition, chemical composition, inorganic nitrogen conversion efficiencies and reactive oxygen species (ROS) generation. The results showed that both nano- and microplastics inhibited the growth of H. alkaliphila in high concentrations, while nanoplastics rather than microplastics influenced the growth inhibition, chemical composition and ammonia conversion efficiencies of H. alkaliphila at concentration of 80 mg/L. The ROS generation indicated oxidative stress induced by nano- but not microplastics, and the oxidative stress induced by nanoplastics may provide a significant effect on bacteria. Furthermore, the positively charged nanoplastics (amine-modified 50 nm) induced higher oxidative stress toward bacteria than that induced by negatively charged nanoplastics (non-modified 55 nm). The increased extracellular polymeric substances as evidenced by transmission electron microscope (TEM) observation suggested the possible bacterial protective mechanisms. The present study illustrates for the first time the impact of plastics debris on the inorganic nitrogen conversion efficiencies of marine bacteria. Our findings highlight the effects of microplastics on the ecological function of marine organisms.

Xuemei Sun, Bijuan Chen, Qiufen Li, Nan Liu, Bin Xia, Lin Zhu, Keming Qu, Science of The Total Environment, Volume 642, 15 November 2018, Pages 1378–1385

The article

Abundance and characterization of microplastics in the coastal waters of Tuscany (Italy): The application of the MSFD monitoring protocol in the Mediterranean Sea

Monitoring efforts are required to understand the sources, distribution and abundance of microplastic pollution. To verify the abundance of microplastics along the Tuscan coastal waters (Italy), water-column and surface samples were collected in two seasons across four transects at different distances to the coast (0.5, 5, 10 and 20 km), within the implementation of the European Marine Strategy Framework Directive. The results show an average concentration of 0.26 items/m3 in the water-column samples and 41.1 g/km2 and 69,161.3 items/km2 of floating microplastics, with an increase with the distance to the coast The seasonality and the sampling area do not affect the abundance of microplastics. The most abundant size class is 1–2.5 mm as fragments and sheets suggesting that fragmentation of larger polyethylene and polypropylene items could be the main source of microplastics. These data represent the application of a harmonized protocol to make the data on microplastics comparable and reliable.

Matteo Baini, Maria Cristina Fossi, Matteo Galli, Ilaria Caliani, Tommaso Campani, Maria Grazia Finoia, Cristina Panti, Marine Pollution Bulletin, Volume 133, August 2018, Pages 543–552

The article

Investigating microplastic trophic transfer in marine top predators

Microplastics are highly bioavailable to marine organisms, either through direct ingestion, or indirectly by trophic transfer from contaminated prey. The latter has been observed for low-trophic level organisms in laboratory conditions, yet empirical evidence in high trophic-level taxa is lacking. In natura studies face difficulties when dealing with contamination and differentiating between directly and indirectly ingested microplastics. The ethical constraints of subjecting large organisms, such as marine mammals, to laboratory investigations hinder the resolution of these limitations. Here, these issues were resolved by analysing sub-samples of scat from captive grey seals (Halichoerus grypus) and whole digestive tracts of the wild-caught Atlantic mackerel (Scomber scombrus) they are fed upon. An enzymatic digestion protocol was employed to remove excess organic material and facilitate visual detection of synthetic particles without damaging them. Polymer type was confirmed using Fourier-Transform Infrared (FTIR) spectroscopy. Extensive contamination control measures were implemented throughout. Approximately half of scat subsamples (48%; n = 15) and a third of fish (32%; n = 10) contained 1–4 microplastics. Particles were mainly black, clear, red and blue in colour. Mean lengths were 1.5 mm and 2 mm in scats and fish respectively. Ethylene propylene was the most frequently detected polymer type in both. Our findings suggest trophic transfer represents an indirect, yet potentially major, pathway of microplastic ingestion for any species whose feeding ecology involves the consumption of whole prey, including humans.

S. E. Nelms, T. S. Galloway, B. J. Godley and al., Environmental Pollution, Volume 238, July 2018, Pages 999-1007

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