Geoquímica orgânica do sistema estuarino Sergipe-Poxim: marcadores moleculares e poluição

• Ano de defesa: 2019
• Autor(a) principal: Souza, Michel Rubens dos Reis
• Orientador(a): Alexandre, Marcelo da Rosa
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Química
• Palavras-chave em Português: Química; Águas residuais; Aspectos ambientais; Esgotos; Avaliação de riscos ecológicos; Estações do ano; Matéria orgânica; Sazonalidade; Esgoto; Risco ecológico
• Palavras-chave em Inglês: Organic matter; Seasonality; Sewage; Ecological risk
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/11137

The Sergipe-Poxim estuarine system is located in the urban area of Aracaju city, Northeast of Brazil. This system has a great socioeconomic importance, however, it has been suffering by a negative contribution from the Aracaju city, being connected to sewage canals, domestic and industrial, as well as connected to Atlantic Ocean, which is known by the offshore petroleum exploration. The aim of this study was to analyze the organic geochemistry of Sergipe-Poxim estuarine system using molecular markers sterols and polycyclic aromatic hydrocarbons (PAH) in superficial water and sediments, and oyster (Crassostrea sp.). The samples collect were performed in two periods, 2017/March (dry season) and 2017/August (rainy season). In the sediment, it was observed the dominance of sterol β-sitosterol at both periods. In all the sampling sites, coprostanol levels were higher than 100 ng g−1, indicating sewage contamination. Diagnostic ratios between coprostanol, cholesterol, and cholestanol confirmed predominance of untreated sewage sources. The PAH were analyzed in the tree matrices, presented low concentrations. The tide effect was determinant to differentiate the HPA levels in water between periods. In the samples of water and oysters prevailed the low molecular weight PAH, while in the sediments, the high molecular weight PAH, being the pyrolytic source priority to the all matrices. The PAH ecological risk index, calculated for water and sediments, were moderate to the maximum permitted concentration (MPCs). The bioaccumulation factor (BAF) was estimated to predict the relationship between bioavailability of HPA detected in the oysters from sediment and water and, in some samples, it was observed influence of fine sediments, as well as of suspended particulate matter. Principal Component Analysis (PCA) and Pearson's correlation test were used to differentiate the seasonality and/or sources of the compounds in the environment. Therefore, it has been observed that the estuary system needs urgent corrective measures.