Revista Brasileira de Ciências Ambientais

Hybrid neural network for daily streamflow projection on a sub-seasonal timescale

Sat, 28 Feb 2026 00:00:00 -0300

Forecasts of hydrological variables are extremely important for water resource management in regions that are particularly vulnerable to the effects of climate change and climate variability. The aim of this study was to develop a hybrid neural network capable of producing daily streamflow forecasts on a sub-seasonal scale. This hybrid neural network consists of an artificial neural network with inputs preprocessed by the wavelet transform (WANN). The WANN was tested in the Três Marias, Sobradinho, and Retiro Baixo reservoirs, located in the São Francisco River Basin (SFRB). The obtained results show that WANN was highly accurate in short-term forecasts (7–28 days); however, for long-term forecasts (35 and 42 days), there was a significant drop in performance, especially during the transition periods to the rainy season and in the dry months. The comparison between the performance metrics of the WANN forecasts and the National Electricity System Operator (ONS) operational models for the Três Marias, Sobradinho, and Retiro Baixo basins showed that WANN outperformed all these models. The results obtained show that WANN is a valuable tool for addressing the complex and dynamic challenges of hydrology, making it essential for decision-making on water resource management.

Bisphenol A Acute Toxicity to the Macroinvertebrate Chironomus sancticaroli (Diptera, Chironomidae) and Sensitivity Analysis of the Species to BPA Analogs

Suzelei Rodgher, Driele Tavares, Maiconn Vinicius de Moraes — Sun, 22 Feb 2026 00:00:00 -0300

Due to concerns about the potential health risks associated with bisphenol A (BPA), several alternatives have been developed. The most common BPA analogs include bisphenol F (BPF) and bisphenol S (BPS). The objective of this study was to evaluate the sensitivity of the tropical macroinvertebrate Chironomus sancticaroli to BPA by performing acute toxicity tests. In addition, species sensitivity distribution (SSD) curves were constructed to compare the sensitivity of C. sancticaroli to different taxonomic groups when exposed to BPA, as well as to evaluate the sensitivity of varying freshwater organisms exposed to BPF and BPS, addressing the SSD analysis. The Predicted No-Effect-Concentrations (PNECs) values of bisphenols were calculated. The average value of the 48-h EC50 of BPA based on the measured concentration for the first instar larva of C. sancticaroli was 6.71 mg L⁻¹. The SSD curve of BPA demonstrated that C. sancticaroli presented an intermediate sensitivity to BPA when compared to two other chironomid species commonly used in toxicity tests. As demonstrated by PNECS values developed in the present study, the order of toxicity based on all species was BPA > BPF > BPS. This study highlights the need to expand data on the acute and chronic toxicity of BPA and its analogs for tropical freshwater biota to estimate potential effects of bisphenols.

Assessment of metal contamination in Tecoma stans (L.) Kunth (Bignoniaceae) pollen samples from urban environments

Thu, 12 Feb 2026 00:00:00 -0300

Urbanization profoundly alters ecosystems, introducing various pollutants, including metals, which degrade environmental quality and pose risks to biodiversity, notably affecting pollinators like bees. Pollen, collected by bees during foraging, can serve as a bioindicator for assessing urban environmental quality, as it accumulates airborne and soil-derived contaminants. Studying metal concentrations in urban pollen is therefore critical, not only for monitoring pollution levels but also for understanding the potential toxicological impacts on bee populations, whose health is intrinsically linked to the quality of their food resources. This study aimed to assess the level of metal contamination in pollen samples of Tecoma stans (L.) Kunth, a plant species commonly found in urban settings and frequently visited by bees for foraging. Pollen samples were collected in the urban area of Uberlândia, MG, in 2023. Using spatial analysis of the city, sampling locations with distinct Bee Environmental Quality Index (BEQI) classifications — low, medium, and very high environmental quality — were selected to investigate the influence of environmental quality on metal concentrations. For this purpose, pollen samples from T. stans flowers were collected and analyzed at the designated sites, and the concentrations of aluminum (Al), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), and magnesium (Mg) were quantified using inductively coupled plasma optical emission spectrometry. Statistical analysis, including PERMANOVA, indicated no significant differences in overall metal profiles across locations with varying BEQI levels, suggesting widespread metal presence regardless of the perceived environmental quality for bees. Principal component analysis and cluster analysis revealed a strong positive association among Fe, Cd, Cr, and Mn, suggesting common origins, while Ca and Cu showed a negative association. Our findings highlight that bees in urban areas are exposed to widespread metal contamination, even in environments classified as having very high BEQI.

Management of agricultural solid waste in the Brazilian semi-arid region: diagnosis and proposals for the Rafael Fernandes Experimental Farm — Brazil

Fri, 06 Feb 2026 00:00:00 -0300

The rising amount of solid waste in rural areas, especially from agro-pastoral activities, has raised concerns about environmentally sound and sustainable waste management. In this context, the Rafael Fernandes experimental farm (RFEF) aims to improve how it handles waste generated from its research activities. The study plans to systematically analyze waste management at RFEF, identify operational weaknesses and legal issues, and support proposals for technical improvements to the waste management system. The research included a review of relevant technical, scientific, and legal aspects; a qualitative diagnosis with illustrations; visits to agro-pastoral areas; photographic documentation of waste handling; and an assessment of environmental liabilities. The findings showed inefficiencies in the segregation and temporary containment of waste, notably the lack of proper containers and standardized labeling for waste types. There was also no clear schedule for internal waste collection and transportation, leading to material buildup in experimental zones. Additionally, issues were found in storing hazardous waste, such as pesticide packaging that failed to meet safety standards. These results emphasize the need to implement a solid waste management plan, provide ongoing staff training, and upgrade infrastructure to promote sustainable waste practices on the farm.

An empirical investigation on undergraduate students’ perception and assessment of sustainability education

Ferdous Ahmed, Adnan Chowdhury, Tamanna Siddiqua Ratna, Md. Sohel Rana — Sat, 17 Jan 2026 00:00:00 -0300

Achieving the Sustainable Development Goals (SDGs) by 2030 remains one of the vital global priorities, and Bangladesh is no exception. A key pathway to meeting these goals lies in educating graduates in sustainability to ensure national and global development. The integration of sustainability knowledge into higher education has significantly facilitated the lifelong learning process. At the International University of Business, Agriculture, and Technology, sustainability-focused courses have been incorporated into the undergraduate curriculum since 2013, reflecting a long-standing institutional commitment to fostering sustainable development education in Bangladesh. This study aimed to assess perceptions of sustainability and environmental practices among students on campus; thus, a multinomial logistic regression model was employed as the primary analytical tool. Findings revealed that 91.1% of students demonstrate a sufficient understanding of sustainability, and 93.9% agree that a sustainability-oriented approach positively influences them to change their lifestyles. However, 41.0% of respondents reported that they would participate in on-campus sustainability projects, while 47.8% strongly agreed, demonstrating a gap between awareness and active involvement. Lastly, this study suggests that increasing the number of undergraduate sustainability-focused courses offered by universities can enhance a country’s ability to promote sustainability-related projects. These improvements in education are likely to lead to an increase in the number of graduates who show greater concern for sustainability and are eager to become involved in environmental initiatives both on- and off-campus. Consequently, this aids in global and national endeavors to accomplish the SDGs by 2030.

Chemical characteristics of size-segregated particles from a brazilian coastal megacity

Mon, 05 Jan 2026 00:00:00 -0300

Particulate matter (PM) size distribution samples were collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) in Rio de Janeiro between July and September 2016 during the Olympic and Paralympic periods, when there was an increase in tourist flow, changes in the local economy, modifications in traffic and pollution emission patterns. The samples were analyzed for elemental composition using inductively coupled plasma mass spectrometry (ICP-MS), for organic and inorganic ions using ion chromatography, and for polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry (GC/MS). The data were processed, interpreted, and discussed through statistical analyses performed in R Language, including boxplots and Pearson correlation methodology. Results were categorized according to particle size: coarse, fine, ultrafine, and nano. Chloride dominated the coarse particulate matter (PMC; 18–3.2 μm), NO₂⁻ the fine fraction (PMF; 1.8–0.56 μm), and HCOO⁻ the ultrafine fraction (PMN; 320–56 nm). Ni, Pb, Sb, and V were enriched in PMN. Four- and five-ring PAHs were predominant across all particle size groups. The species present in the coarse fraction come from natural sources, while those in the fine fraction are of anthropogenic origin, mainly from the combustion of diesel and gasoline by vehicle engines.

Hot spots and their climatic, environmental, and social determinants in the Cuiabá River Headwaters Environmental Protection Area, Brazil

Mon, 05 Jan 2026 00:00:00 -0300

The State Environmental Protection Area of the Cuiabá River Headwaters, located in the Cerrado biome, experiences recurrent wildfires that threaten its ecological integrity. This study analyzes the spatiotemporal dynamics of fire activity between 2010 and 2019, focusing on the relationship between climatic variables and the occurrence of hot spots. Data on hot spots were sourced from the fire database of the Brazilian National Institute for Space Research, while climate variables — precipitation, air temperature, and relative humidity — were obtained from the Brazilian National Institute of Meteorology database. Monthly fire activity was statistically correlated with climatic conditions using Spearman’s correlation, and the number of consecutive dry days was calculated to assess drought severity. The results revealed a significant increase in hot spot density during the dry season (August to October), strongly associated with low precipitation, high temperatures, and critically low relative humidity. Among these variables, relative humidity showed the strongest and most consistent correlation with fire incidence, evidencing its role as an immediate meteorological trigger. Spatial analysis using kernel density estimation confirmed the concentration of fire activity in areas with recent land use changes, particularly agricultural expansion zones. These findings highlight the role of compound drought–fire dynamics in shaping fire regimes in the Cerrado and support the adoption of climate-informed fire management strategies to reduce wildfire risk in protected areas.

Anthropogenic impacts on water quality in southern Brazil: a multidimensional analysis of tributaries and the Chavantes reservoir

Mon, 05 Jan 2026 00:00:00 -0300

Freshwater is a vital resource, and its quality is critical for both human and environmental health. This study evaluated physicochemical and microbiological parameters of water from the Chavantes Reservoir, upstream tributaries to the reservoir, and downstream sites in the Paranapanema River and in its downstream tributaries, as well as the antimicrobial susceptibility of Escherichia coli. The results showed that variables such as temperature, turbidity, and total dissolved solids remained within the limits established by Brazil’s Environment Council (CONAMA) Resolution 357/2005 and Minister’s Office/ Ministry of Health (GM/MS) Ordinance 888/2021. In contrast, thermotolerant coliforms and E. coli exceeded the permitted values in several tributaries upstream. A strong correlation was observed between turbidity and coliforms, indicating fecal pollution sources related to the lack of sanitation and inadequate waste management. Antimicrobial resistance analysis revealed the presence of tetracycline- and gentamicin-resistant genes in E. coli strains, highlighting the impacts of agricultural activities and the indiscriminate use of antibiotics. Principal component analysis indicated greater dispersion among the upstream tributaries, reflecting high variability, while reservoir samples exhibited lower microbiological contamination, suggesting a dilution effect. These findings reinforce the need for continuous monitoring, riparian zone restoration, and the implementation of integrated sanitation and environmental management strategies. This study contributes to understanding anthropogenic impacts on water resources and supports public policies aimed at conserving water quality in the Chavantes Reservoir region.