Polycyclic aromatic hydrocarbons in surface water of rivers in Sergipe State, Brazil: A comprehensive analysis of sources, spatial and temporal variation, and ecotoxicological risk.

This study conducted in Sergipe State, Brazil, aimed to investigate the presence of polycyclic aromatic hydrocarbons (PAHs) in the surface water of five rivers, determining their sources, spatial and temporal variations, and ecotoxicological risks. Correlation and principal component analyses were utilized to identify the relationship between PAH concentrations and water sample properties. Results indicated higher PAH concentrations during the rainy season, attributed to increased run-off and sediment resuspension. The composition of PAHs suggested a main petroleum source with organic material combustion in minor scale. Ecological risk assessment revealed potential risks to the ecosystem, emphasizing the need for continuous monitoring of PAHs pollution. This study highlights the importance of understanding and mitigating PAHs contamination in rivers to protect aquatic ecosystems.

The impact of anthropogenic activity at the tropical Sergipe-Poxim estuarine system, Northeast Brazil: Fecal indicators.

The individual concentrations and sources of sterols in sediments samples collected in two periods 2017 (dry period /March and rainy period/August) were determined along with the Sergipe-Poxim estuarine system, Aracaju, Brazil. The individual sterols concentration ranged from 135 to 21,746 ng g-1 (March) and 191 to 144,748 ng g-1 (August) and the distribution was mainly dominated by ß-sitosterol in both periods with 37.2% (March) and 70.8% (August) of the total sterols found. In all the sampling sites, the coprostanol levels were higher than 100 ng g1 (March) and 500 ng g-1 (August), indicating sewage contamination. Diagnostic ratios between sterols suggested the predominance of sewage sources. Pearson correlation assessed a correlation significant (March) and negligible (August) between coprostanol concentration levels and organic matter. The principal component analysis (PCA) showed that the sterols levels influenced strongly C1, as well as C2 distinguished between the plant sterols and from sewage.

Polycyclic aromatic hydrocarbons in sediments of the Amazon River Estuary (Amapá, Northern Brazil): Distribution, sources and potential ecological risk.

The distribution, sources and potential ecological risk of priority polycyclic aromatic hydrocarbons (PAHs) in sediment from the Amazon River Estuary (Macapá and Santana, Amapá, Northern Brazil) were investigated. The total PAHs concentration (∑PAH) ranged from 22.2 to 158.9 ng g-1 dw (mean value 49.4 ng g-1 dw). PAHs levels in the study area were relatively low than those in nearby areas and other coastal zones worldwide, and could be considered as baseline for PAHs in Amazonic sediments. PAHs ratios and the statistical analysis showed that fossil fuel and biomass combustions, primarily from local sources, were the dominant PAHs origins. The potential ecological risk was assessed on the basis of the sediment quality guidelines, and it was found that PAHs in the sediments of the Amazon River Estuary do not cause adverse effects on living organisms; however, the abundance of naphthalene and the presence of dibenzo[a,h]anthracene and benzo[a]pyrene deserve more attention.