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Honey, traditionally known as a pure and natural substance, has become an unexpected reservoir for microplastic contamination. This study consisted of an experimental investigation to assess the occurrence of microplastics in honey produced by Melipona quadrifasciata, a native bee species in Brazil. Our investigation covers eight areas (one sample per area), including built and vegetated areas located in São Paulo city, Brazil, to understand the distribution of microplastics in these environments. Honey samples (10 mL) were collected using a syringe and sent to the laboratory for further analysis. Microplastics extracted from honey samples were characterized under a stereomicroscope to determine their size, color, and morphology. Also, the polymer type was determined by FTIR analysis. All honey samples (100%) showed microplastics. The predominant particles displayed a fiber shape with a size below 299 μm and a transparent color and were primarily composed of polypropylene. Their concentrations ranged from 0.1 to 2.6 particles per mL of honey, raising concerns about their potential impact on bee populations and human consumers. This study underscores the need for further research on the sources and implications of microplastic contamination in Melipona quadrifasciata honey, shedding light on the broader issue of environmental plastic pollution and its impact on pollinators. [ABSTRACT FROM AUTHOR]

Freshwater environments are especially susceptible to microplastic contamination due to their proximity to urbanised and industrial areas. Also, there is a lack of information about the effects of this pollutant on freshwaters making it difficult the conservation of these environments. Benthic species, such as the freshwater amphipod Hyalella azteca, have been superficially studied so far for evaluation of microplastic pollution. In the present study, we analyzed whether polyethylene terephthalate (PET) microplastics could lead to reduced survival of H. azteca or changes in biochemical markers (SOD, CAT, MDA, and GST) at environmentally relevant concentrations (60 and 600 particles) after 7 d of exposure. The results showed that there was no significant mortality at any of the concentrations tested. The enzyme CAT showed no variation compared to the control group at any of the concentrations. SOD, MDA, and GST were statistically different (p < 0.05). Our study demonstrated that PET MP did not affect the survival of H. azteca at environmentally relevant concentrations. However, changes in biomarkers of oxidative stress may be detected at low level of exposure (60 particles). Although survival is not affected, the macrobenthic invertebrate community may be under threat in environments where there is PET microplastic pollution. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in the impacts caused by the presence of microplastics (MP) in aquatic environments. The impacts of microalgae exposure to microplastics are still insufficiently investigated and further studies are needed to understand the possible outcomes. In addition, much of the literature has focused on the study of concentrations above those found naturally in the environment and in less toxic polymer matrices. Acrylonitrile-butadiene-styrene (ABS) plastics have a composition rich in additives and, so far, have been studied superficially. In the present study, two of the most commonly used green microalgae species in toxicity assays, Chlorella vulgaris and Raphidocelis subcapitata, were exposed to different concentrations of primary ABS-MP for a period of 6 days. Here, we observed physiological changes in cell growth and chlorophyll a content induced by the concentration and time of exposure to ABS-MP. The lowest concentration did not prove to be potentially toxic to cells, while the highest concentration was the most toxic. Primary consumers, such as microalgae, are essential for the proper functioning of entire ecosystems. Changes in these communities can lead to permanent damage to the communities of organisms at higher levels, so it is essential that their study be done carefully in the face of threats such as MP. Chlorella vulgaris and Raphidocelis subcapitata, were exposed to different concentrations of ABS microplastics during 6 days. We observed physiological changes in cell growth and chlorophyll content in response to the concentration and duration of exposure. [ABSTRACT FROM AUTHOR]

In this study, the corrosion resistance of AA2024-T3 specimens anodized in TSA and subsequently post-treated in a Ce-H 2 O 2 solution and sealed by a hybrid sol–gel coating (3-glycidoxypropyltrimethoxysilane and tetraethoxysilane), with hydrolysis solution aging times of up to 6 months, was investigated by means of electrochemical impedance spectroscopy (EIS). The results demonstrated that, whichever the aging time, the Ce post-treatment enhances the performance of the sol-gel coating; moreover, for both surface conditions, the corrosion protection was maximized for a hydrolysis time of 14 days, even though the corrosion performance of samples protected with the solution aged for 6 months was similar to that aged for 1 day. Correlation of these results with FTIR and viscosity measurements of the aged hydrolysis solution suggest that the protective performance of the coating is heavily influenced by in-solution condensation reactions; excessive condensation leads to the formation of oligomers, resulting in increasingly flawed coatings with specific delamination points as revealed by SEM imaging. The relatively long shelf life of the hydrolysis solution is a good prospect for the industrial use of the proposed treatment. [ABSTRACT FROM AUTHOR]