Revista Brasileira de Ciências Ambientais

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

2025-10-29T12:23:15-03:00

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

2025-10-15T09:28:13-03:00

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

2025-07-01T09:46:48-03:00

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.