Microplastics are omnipresent in the atmosphere, terrestrial and aquatic ecosystems, food and beverages. They may cause risks to biodiversity and the human population. The present study aims to assess the concentrations of microplastics in raw and drinking water of the Sinos River in Southern Brazil. The water was collected at eight locations along the Sinos River and in eight residences supplied with treated river water. The samples were processed by dying plastic particles with Nile Red and counting by fluorescence microscopy. River water showed an average of 330.2 particles L−1 and treated water 105.8 particles L−1. Fibers were the most abundant particles shapes in the samples. Particle abundance in the raw water did not follow the urbanization gradient in the Sinos River basin. The exact pathways of microplastic particles remain unidentified, but the predominance of fibers suggests that untreated sewage from washing machines may be a principal source of contamination, particularly in the headwaters. The microplastic in the drinking water is an additional factor to be considered in conservation efforts aiming at improving water quality in the Sinos River basin.

This study investigated the occurrence of plastic particles in the digestive tracts of fish from headwater streams in a human-thinly populated region of the subtropical Sinos River basin in southern Brazil. In total, 258 individuals from 17 species were collected using electric fishing. Thirty-eight percent (38%) of the specimens contained plastic particles. All of them were fibers, with a maximum count of 43 per individual. Plastic fibers were the fourth most abundant food category. Results showed that the uptake of these plastic particles was proportional to the number of ingested food items. Fiber counts in the guts correlated with the uptake of Trichoptera, which are invertebrates using plastic particles to construct their protective cases. No significant difference in plastic uptake was detected between benthic and water column fish. No evidence of bioaccumulation of plastic particles was found in the intestines. The distance from urban areas was not related to the number of ingested plastic particles, concluding that plastics are ubiquitous and available to biota, even in remote locations. The most probable source of these particles is residences close to the streams which discharge the sewage of washing machines without any treatment.

The brittle behavior of concrete can be compensated by the addition of reinforcements, providing benefits such as improved crack control, residual strength and increased flexural strength. It is usual to apply mono fibers to concrete, but their positioning in the matrix may not be homogeneous, consequently increasing the susceptibility to fracture planes with fewer reinforcements. This study aimed to evaluate the use and behavior of simple (mono) and space (3D) steel fibers (SE), in order to achieve a more homogeneous mixture, increase the effectiveness of fibers in restricting cracks and improve mechanical properties. The fresh-state was assessed through slump and VeBe tests, whereas the hardened-state tests comprised axial compressive strength, flexural strength and the flexural toughness factor. The volume content of simple and space fibers varied from 0 to 0.93%. Based on the results, it can be stated that space and simple fiber contents improved rheological and mechanical properties of the composite in isolated (0.29%) and hybrid (0.64%) combinations, since their overall performance exceeded the other mixtures’. However, space fibers caused considerable workability losses compared to the conventional concrete, hindering its casting and harming its hardened-state properties.

No abstract

No abstract