DETERMINAÇÃO DE MARCADORES ORGÂNICOS NO PERFIL SEDIMENTAR DO COMPLEXO ESTUARINO DE PARANAGUÁ (PR) POR CG-EM

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The input evaluation of the organic matter in aquatic environment by anthropic activity can be done by the identification and quantification of molecular markers. Many studies point the application of the molecular markers for this objective but few of them evaluate the variation of the compound concentration through a long period of time registered on the sedimentary layers. The present work elaborates a study using three molecular markers on the sedimentary profile of the Paranaguá Estuary Complex (CEP) at Paraná, which in the later years the anthropic activity has been raising. This work has as objective to identify the main sources of organic matter and to study the background of these inputs on the CEP sedimentary column relating the sedimentation rates with the natural and anthropic deposition. The valid legislation for the environmental watching, in the matter of fecal sewer contamination, suggests and evaluation by chemical indicators such as fecal steroids (ex: coprostanol), it is a very promising alternative because theses are endurable, even being less sensitive to environmental variations. The other two environmental anthropic input molecular markers which will be determined in this study are the linear alkylbenzenes (LABs), existing on detergents, which indicates anthropic inputs derived from domestic sewer and caffeine, being aware that fecal steroids can be obtained by warm blooded animal excrement, indicating other sources. For the present work, were collected 12 cores with depth down to 1 m in the date of may, 2006, summing up 12 assessing points and a quantity of 121 samples. The analyses were made by gas chromatography-mass spectrometry (GC-MS). The steroids found with higher concentration were β-sitosterol (71.4 μg g-1), stigmasterol (8.7 μg g-1), cholestanol (3.6 μg g-1) and stigmastanol (2.8 μg g-1), all of them derived from natural sources, indicating that the main CEP contribution is by biogenic input. Coprostanol, which is a fecal steroid, was found in concentrations between 0.001 e 4.10 μg g-1, other two fecal derived steroids were also detected, epicoprostanol and coprostanone, with concentration 3.6 e 0.2 μg g-1, respectively, these higher concentrations were found near urban area, indicating anthropic origin. The higher ΣLAB concentrations were also found in regions near the city of Antonina and Paranaguá, being the most found in the core #3 Gererês (208 ng g-1). The last molecular marker analyzed, the caffeine, was found in its higher concentration, 18.41 ng g-1, this point being located far off from urban centers, but this contaminant, very soluble, can be transported in water column and travel great distances. Through the analyzed compounds, can be noticed that the antropogenic intervention stood out on the collected cores of CEP east-west axis, staying registered on the sedimentary layers.

ASSUNTO(S)

paranaguá molecular markers esteróides quimica sedimentary core perfil sedimentar paranaguá cafeína marcadores moleculares

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