Microplastic pollution in aquatic ecosystems has drawn attention not only because microplastics are likely to accumulate anywhere but also because they cause negative impacts both to aquatic biota and, indirectly, to public health, as a result of their presence. The understanding of the distribution and accumulation patterns of this “new contaminant” is fundamental for the calibration of environmental risk studies. However, research on its migration pattern and consequent distribution is still limited. The present study has focused on the peculiar physical characteristics of plastic microparticles and the response to environmental factors such as hydrodynamics and physical chemistry of water on the diffusion dynamics of these pollutant agents. Therefore, we examined information about the vertical abundance distribution, the composition, and the sizes of microplastics, along with the varied aquatic environments existing on Earth. This study provides valuable evidence for the accumulation trend of microplastics across the environment and the peculiar particle characteristics that dictate their distribution patterns. The present study concluded that detailed studies should be carried out in order to add information about the behavior of plastic microparticles in aquatic environments and thus subsidize the calibration of existing information, thus increasing its accuracy in understanding the diffusion patterns of these polluting agents.

Although plastic is ubiquitous in marine systems, our current knowledge of its transport is limited. Recent studies suggest size-selective removal of small plastic particles (<5 mm) from the ocean surface as a result of the formation of a biofilm (the “plastisphere”) on the microplastic particle (MP) surface. This localized microenvironment can isolate the microcosm from the adjacent aqueous medium, and thus protect component alien species from the surrounding physico-chemical conditions. Apart from resulting in specific conditions for the transfer of alien species through the environment, the plastisphere can impact MP hydrodynamics and cause MPs to move through the water column, initially sinking. The importance of this phenomenon has not been previously considered for these particles. The size-dependent vertical movement of MPs through the water column determines their distribution, which will vary with time of exposure and colonization. Some plastisphere organisms have plastic-degrading activities, which could be harnessed in marine depollution strategies. This article seeks to increase our understanding of the role of biofilms in the biological dynamics and diffusion of plastic microparticles.

Groundwater pollution is a current issue that may result in considerable negative effects on human health and the ecological balance. In the present study, the authors evaluated pollutants in groundwater in Maricá Municipality, located on the east side of Rio de Janeiro state in Brazil. The evaluated parameters were temperature, pH, electrical conductivity, Eh, dissolved oxygen, chlorides, nitrates, dissolved organic carbon, total inorganic carbon, phosphates, and total and thermotolerant coliforms. Due to the large number of evaluated points, they were divided into zones according to the respective hydrographic basin. The local accelerated urbanization accompanying income from oil production has led to uncontrolled population growth and associated groundwater pollution. The results of the present study suggest that sewage pollution of Maricá groundwater is already a significant issue. The lack of investment in basic sanitation has led to an imbalance in the local groundwater reservoir. In certain locations of the municipality, dissolved organic carbon (DOC), nutrient, and bacteria concentrations increase and spread in the aquifers because of domestic waste disposal. As aquifers are the main source of freshwater for the residents, contamination of them represents a potential threat to local public health.

The Santos Estuarine System (SES), located in southwest Brazil, presents strategic economic importance for the country due to the presence of the biggest Brazilian Port and for being one of the most industrialized areas. On the other hand, this environment is adversely impacted by industrial and dredging activities, which can cause environment pollutants enrichment and potential hazard compound bioavailability. In this context, Polycyclic Aromatic Hydrocarbons (PAH) were assessed in fifteen sampling stations distributed along the estuary. Polycyclic aromatic hydrocarbon (PAH) concentrations were analyzed in surface sediment samples and two bivalve species’ tissues (Crassostrea rhizophorae and Perna Perna). In addition, water column salinity, sediment organic matter, and grain size were analyzed to check their influence on the contaminant accumulation. Total PAH sediment concentrations ranged between N.D. and 1711.79 ng g-1 dry weight (d.w.). Bivalve hydrocarbon levels varied between 88.38 and 988.76 ng g-1 (d.w.). The calculated PAH ratios revealed that the PAH compounds found in the studied area has both petrogenic and pyrolytic origins. A comparison of the PAH concentrations found in this study with those listed in the sediment quality guidelines (SQGs) indicated that adverse biological effects on the biota are eventually expected. Keywords: Polycyclic Aromatic Hydrocarbon; Contamination; Industrial Activities. O Sistema Estuarino de Santos (SES), localizado no sudoeste do Brasil, apresenta importância econômica estratégica para o país devido à presença do maior porto brasileiro e por ser uma das áreas mais industrializadas. Por outro lado, este ambiente é prejudicado pelas atividades industriais e de dragagem, que podem causar o aumento de poluentes ambientais e a biodisponibilidade de compostos potencialmente perigosos. Neste contexto, os hidrocarbonetos policíclicos aromáticos (HPA) foram avaliados em quinze estações de amostragem distribuídas ao longo do estuário. As concentrações de HPA foram analisadas em amostras de sedimentos superficiais e em tecidos de duas espécies bivalves (Crassostrea rhizophorae e Perna perna). Além disso, analisou-se a salinidade da coluna d'água, a matéria orgânica dos sedimentos e o tamanho dos grãos para verificar sua influência sobre o acúmulo de contaminantes. As concentrações totais de sedimentos HPA variaram entre N.D. e 1711,79 ng g-1 de peso seco (p.s.). Os níveis de hidrocarboneto bivalve variaram entre 88,38 e 988,76 ng g-1 (p.s.). As taxas de HPA calculadas revelaram que os compostos de HPA encontrados na área estudada têm origem petrogênica e pirolítica. Uma comparação das concentrações de HPA encontradas neste estudo com aquelas listadas nas diretrizes de qualidade de sedimentos (SQGs) indicou que os efeitos biológicos adversos sobre a biota são eventualmente esperados. Palavras-chave: Hidrocarbonetos Policíclicos Aromáticos; Contaminação; Atividades Iindustriais.

As a result of their great versatility and use, plastic dies became fundamental as one of the basic raw materials for the technological revolution during the post-World War II period. The significant importance of these “new” materials is confirmed, as many researchers around the globe consider that sedimentary plastic layers as an indicative of the beginning of the Anthropocene Era. Along the industrialization period, annual plastic production has increased from less than two million tons in 1950 to over 350 million tons today, and if current demand continues, it is expected to exceed 30 billion tons by 2050 (Porta, 2021). Como resultado de sua grande versatilidade e utilização, as matrizes plásticas tornaram-se fundamentais como uma das matérias primas básicas para a revolução tecnológica durante o período pós-Segunda Guerra Mundial. A importância significativa desses "novos" materiais é confirmada, pois muitos pesquisadores em todo o mundo consideram que as camadas sedimentares de plástico como um indicativo do início da Era Antropocênica. Durante todo o período de industrialização, a produção anual de plástico aumentou de menos de dois milhões de toneladas em 1950 para mais de 350 milhões de toneladas hoje, e se a demanda atual continuar, espera-se que exceda 30 bilhões de toneladas até 2050 (Porta, 2021).

Endocrine-disrupting compounds (EDCs) are emerging pollutants that can potentially accumulate in aquatic ecosystems at significant levels, with the potential to impact the health of both animals and humans. Many scientists have correlated human exposure to high concentrations of EDCs with critical physiological impacts, including infertility, thyroid imbalance, early sexual development, endometriosis, diabetes, and obesity. Several substances, such as heavy metals, belong to this family, ranging from natural to synthetic compounds, including pesticides, pharmaceuticals, and plastic-derived compounds. Domestic sewage represents a significant source of EDCs in the surrounding aquatic ecosystems. To this day, most rural and urban domestic wastewater in the municipality of Maricá is directly discharged into local aquatic environments without any treatment. The present study aimed to assess the potential contamination of the riverine and lagoonal environment in the municipality of Maricá. Water and sediment samples were collected seasonally at 18 sites along the Maricá watershed and the main lagoon, into which most of the watershed’s contributors flow. Water physico-chemical parameters (pH, reduction–oxidation potential—Eh, dissolved oxygen levels, salinity, turbidity, temperature, and fecal coliforms) were analyzed to characterize the urban influence on the aquatic environment. Sediment samples were also analyzed for grain size, total organic carbon percentage, potential bioavailable fraction of trace metals (Cd, Pb, Cu, Cr, Hg, Ni, Zn), and metalloid As. Finally, the sediment toxicity was assessed using yeast estrogen screen (YES) assays. The results obtained already demonstrate the presence of estrogenic effects and raise concerns about water quality. The current study indicates that, despite the absence of agricultural and industrial activities in the city of Maricá, EDCs are already present and have the potential to impact the local ecosystem, posing potential risks to human health.