Search

Distribution of microplastics particles (MPs) in the water column is investigated on the base of 95 water samples collected from various depths in the Baltic Sea Proper in 2015–2016. Fibres are the prevalent type of MPs: 7% of the samples contained small films; about 40% had (presumably) paint flakes, while 63% contained coloured fibres in concentrations from 0.07 to 2.6 items per litre. Near-surface and near-bottom layers (defined as one tenth of the local depth) have 3–5 times larger fibre concentrations than intermediate layers. Laboratory tests demonstrated that sinking behaviour of a small and flexible fibre can be complicated, with 4-fold difference in sinking velocity for various random fibres' curvature during its free fall. Numerical tests on transport of fibres in the Baltic Sea Proper were performed using HIROMB reanalysis data (2007) for the horizontal velocity field and laboratory order-of-magnitude estimates for the sinking velocity of fibres. The model takes into account (i) motion of fibres together with currents, (ii) their very slow sinking, and (iii) their low re-suspension threshold. Sensitivity of the final distribution of fibres to variations of those parameters is examined. These experiments are the first step towards modelling of transport of fibres in marine environment and they seem to reproduce the main features of fibres distribution quite well. [ABSTRACT FROM AUTHOR]

In a national survey on mortality from malignant pleural neoplasms in Italy, aimed at detecting geographic clusters of cases of the disease, the town of Biancavilla, located in a volcanic area of Eastern Sicily, showed high risk of pleural mesothelioma in the absence of occupational asbestos exposure. An environmental survey suggested the stone quarries located in ‘Monte Calvario’, south–east of the town of Biancavilla, as a possible source of asbestiform fibre exposure. A subsequent crystal-chemistry investigation of the ‘Monte Calvario’ amphiboles identified the mineral asbestiform fibres as ‘fluoro-edenite’, a new end-member of the edenite⇒fluoro-edenite series. A collaborative epidemiological and environmental study was initiated to investigate the characteristics of the outbreak of malignant mesothelioma and test the hypothesis of a causal association with exposure to naturally occurring fibres. To investigate if a sheep population could be used to monitor the environmental diffusion of the fibres, we examined lung specimens from 27 culled sheep, at least 3 years old and living near Monte Calvario to check for the presence of fluoro-edenite fibres, using scanning electron microscopy (SEM) analysis and X-ray microanalysis. Fourteen mineral species have been isolated in the mineral particulate matter taken from pulmonary parenchyma, and fluoro-edenite was detected in eight sheep. These preliminary data suggest a possible bio-indicative role of sheep as sentinel animals in the evaluation of environmental fibre diffusion, which merits further investigation. [Copyright &y& Elsevier]

Microplastics are plastic pieces <5 mm in size that are more harmful than large plastic debris. The world's oceans contain large amounts of these particles, and their presence is severely affecting the marine organisms. Smaller aquatic organisms ingesting microplastics, mistaking them for food, and their subsequent entry into the food chain is of significant concern. Rivers are major carriers of these materials from the terrestrial environment to the oceans. In this study, for the first time, we have done the source-to-sink characterization of microplastics (5 mm–0.3 mm) for a tropical Indian river, namely the Netravathi River, which debouches into the Arabian Sea. Here, we present a detailed investigation made on water, sediments and soil samples collected from the river catchment. All the samples showed the presence of microplastics with a mean numerical abundance of 288 pieces/m3 (water), 96 pieces/kg (sediment) and 84.45 pieces/kg (soil). Fibres, films and fragments are the main categories obtained from the catchment. The microplastics present in the samples were mostly transparent and white coloured which are due to the decay of plastic carry bags, packing materials and fishing lines. Different coloured microplastics were also present in lesser numbers. Polyethylene (PE) and polyethylene terephthalate (PET) are the most abundant polymers present in the samples. Fragmentation of larger plastic materials which is due to mismanaged solid waste and garment washing are the primary sources of these materials in the river catchment. Moreover, the sampling sites near to important pilgrim centres like Dharmasthala and Subrahmanya, register higher concentration of fibres released due to washing of clothes. The study concludes that the Netravathi River is contaminated with microplastics from its origin to the sink. However, the spatial distribution and abundance of microplastic particles demonstrate the influence of population distribution, land use and good household practices of waste management in some areas. Unlabelled Image • A source-to-sink investigation on microplastic pollution in an Indian river. • Microplastics varied in their abundance, composition, morphology and colour. • Polyethylene and polyethylene terephthalate are the abundant polymers in the river. • Packaging materials and fibres from clothes contribute to microplastic pollution. • Anthropogenic activities and hydrodynamic factors affect microplastic distribution. [ABSTRACT FROM AUTHOR]

The reliance on plastic for a vast number of consumer products, many of them single-use, results in their continuous entry into aquatic environments. Plastic waste can fragment into smaller debris, some with a diameter < 5 mm (microplastics). Microplastics are of growing concern especially since 2014, however to date research on microplastic pollution has mainly focused on marine environments, partly because it has been mistakenly thought that sewage treatment plants could remove all plastic debris. To understand the impact of microplastic pollution in freshwater environments, an assessment of research on the sources, distribution and effects of microplastics, and trends in their analysis and policy has been carried out. Main sources of microplastic found in freshwater environments include synthetic textiles, personal care products, industrial raw materials and the improper disposal of plastic waste. Microplastic pollution is a global issue that presents with a broad range of concentration: for example, 3.5 × 10^3 microplastic units·L−1 were reported in sediment of Lake Huron, in the US and as low as 1.2×10−4 units·L−1 in countries with sparse population such as Mongolia. The main polymer constituents of microplastics found in freshwaters have been identified as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET), accounting for 70% of the total, each with a very similar frequency of occurrence. Despite microplastics being relatively inert, they are found to cause some effects in aquatic organisms. Future work should focus on monitoring microplastic pollution in regions from where there is currently scarce published data (e.g. South America, Africa and North Asia) and the study of their sources, stability, transport and effects to freshwater ecosystems. The establishment of standardized monitoring methods will allow for the comparison of data from different geographic areas. This information will inform measures to reduce the release and occurrence of microplastics in aquatic environments. Unlabelled Image • In freshwater, microplastics suffer weathering and distribute around their source. • Effluents from sewage treatment plants, laundry and litter release microplastics. • Fibres are the main type of microplastic in freshwater, followed by fragments. • No high throughput monitoring methods and lack of harmonisation. • Undefined toxicity with a trend showing it is affected by size and shape. [ABSTRACT FROM AUTHOR]