The pollution of aquatic environments has been one of the most impactful environmental quality issues in recent decades. Among the main sources of pollution are industrial waste, agricultural effluents, sewage, heavy metals, and microplastics. Many pollutants are biologically active at low concentrations, resulting in sublethal effects, which makes the situation highly complex and difficult to assess. The Gravataí River is among the ten most contaminated and polluted water bodies in Brazil. However, there is a lack of data in the scientific literature regarding the biological effects of its waters and pollutants. This study aimed to perform an integrated ecotoxicological assessment using Danio rerio and Daphnia magna to evaluate the water quality of the Gravataí River. For this purpose, water and sediment samples were collected at one sampling site considered less impacted (S1) and another located in an area with higher population density (S2). Water samples were analyzed for emerging pollutants, physicochemical parameters, and microplastics, while sediment samples also showed the presence of microplastics. To understand the biological effects caused by these samples, acute and chronic toxicity tests were performed using the Daphnia magna model. Potential teratogenic effects were also assessed in Danio rerio embryos. The results showed high concentrations of estradiol and bisphenol A at both sampling points, which, likely associated with other detected pollutants, resulted in reduced body length and changes in the reproductive patterns of Daphnia magna. No morphological abnormalities or mortality were observed in Danio rerio embryos. These findings highlight the ecotoxicological risks posed by the contaminated waters of the Gravataí River and emphasize the importance of monitoring toxic substances in aquatic ecosystems.
Eupsittula cactorum is among the most trafficked psittacine birds in northeastern Brazil. Birds involved in trafficking often lose their ability to fly due to captivity conditions. This study aimed to assess the effectiveness of (i) environmental enrichment, (ii) flight training, and (iii) feather imping in improving the flight conditions and rehabilitation of E. cactorum. Of the 10 captive birds evaluated, two of them had their wing feathers clipped, and feather imping was performed on one of those two. Behavioral assessment was conducted before and during the application of environmental enrichment. Flight training was provided, and a flight capacity assessment test was performed before, during, and after the application of the methodologies. There was a statistically significant increase in exploratory activities, such as foraging and movement, following environmental enrichment. After flight training, 90% of the group showed improvement in flight score. Only the bird that did not receive the feather imping remained unable to fly and could not be reintroduced into the wild. This is the first study to perform feather imping on E. cactorum. Environmental enrichment, flight training, and feather imping played a crucial role in reducing the rehabilitation period of the cactus parakeet, accelerating its release into the wild.
The Brazilian coastal zone comprises a wide range of environments, including lagoons and beaches, which were selected for this study. Coastal lagoons are wetlands currently subjected to impacts caused by anthropogenic activities, whereas beaches form one of the most extensive systems in the world and are shaped by dynamic processes that continually alter their configuration. Both environments are highly important and harbor a wide variety of organisms, including benthic meiofauna, which plays a fundamental role in understanding the structure and functioning of marine communities. In this context, this study used meiofauna as an indicator of environmental quality in three marine-influenced areas located in the Golfão Maranhense, using the Nematoda/Copepoda index. Sediment samples were collected from São Marcos Beach, Calhau Beach, and Jansen Lagoon for meiofaunal, granulometric, and organic matter analyses. Variables of the interstitial water were also measured. A total of 7,254 meiofaunal organisms were identified and distributed among 10 taxa. Salinity was the main factor structuring meiofaunal communities. The Ne:Co ratio varied significantly among areas, suggesting different levels of contamination. These data provide a comprehensive overview of environmental conditions and meiofaunal assemblages in the three study areas, highlighting the importance of salinity in habitat structuring and the need for conservation measures to preserve biodiversity and ecological quality in these environments.
Limnoperna fortunei (Dunker, 1857): investigating colonization patterns. Limnoperna fortunei is a bivalve species native to Asia that was introduced in 1991 to South America in the River Platen basin (Argentina) through ballast water from Asiatic ships. The proliferation of this species causes several environmental impacts, such as the loss of biodiversity, and economic impacts, especially due to its capacity for macro-fouling in different types of substrates, which can cause obstructions in structures like hydroelectric plant pipelines. In this context, the aim of the study was to perform a scientometric analysis of publications on experimental approaches to the colonization of L. fortunei in different substrates. For this purpose, articles published up to 2024 were extracted from the Web of Science database and analyzed. The analysis revealed that the number of publications increased over the years and that Brazil was the country with the highest number of publications. There was a predominance of short-term research, the river was the most studied environment, and temperature was the most analyzed variable. The publications also revealed that plastic was the most used substrate for fouling organisms and that most substrates were suspended between 0 and 199 cm. This is worrying because the pollution of aquatic environments by plastics can favor the invasion of this species. Finally, the study showed that, given the number of publications selected, there are still gaps in studies on the colonization of L. fortunei that need to be filled through the expansion of experimental studies, especially with regard to research that uses substrates for the bivalve's colonization.
Methylene blue (MB) is a widely used dye present in industrial effluents, particularly from the textile sector, and also has medical and disinfectant applications. As a persistent contaminant, MB poses environmental concerns. We evaluated the applicability of an advanced oxidation process for MB degradation using a 1 L reactor equipped with iron cathodes and a graphite anode. Current densities of 8.93, 17.86, and 26.79 mA cm–2 were tested at pH 3, 7, and 10. MB concentrations were monitored by ultraviolet–visible spectrophotometry over 60 minutes with sampling at 5, 10, 20, 30, 45, and 60 minutes; pH, temperature, electrical conductivity, and voltage were also recorded. Complete MB removal was achieved at pH 7 with a current density of 26.79 mA cm–2. Notably, pH 7 (Experiment 5) was close to the raw sample pH, indicating that the process can operate efficiently without extensive pH adjustment and may offer relatively low operating costs for MB removal.
