Uso de marcadores orgânicos moleculares na determinação da origem da matéria orgânica em sedimentos do Sistema Estuarino-Lagunar de Cananéia-Iguape - SP - Brasil / Use of organic molecular markers in determination of the origin of the organic matter of Estuarine-Lagunar System of Cananeia-Iguape

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

This work has the objective in evaluate the sources of organic matter in sediments of the Cananéia-Iguape Estuarine-Lagunar System, using several geochemical markers. For the study area, 12 sample points were chosen, where the corers were obtained. For each point, the superficial 10 centimeters, sliced in each 2 centimeters, totalizing 60 samples. Granulometric analysis, C/N and 13C/12C ratios and dating of some cores, were realized by the Geological Oceanography group of IOUSP. The molecular organic markers used were the aliphatic hydrocarbons, fatty alcohols and steroids, analyzed by GC-FID. The total hydrocarbons varied from 0.571 to 9.932 g g-1. The total fatty alcohols ranged from 0.318 to 35.291 g g-1. The total steroids varied from 0.241 to 11.054 g g-1. For interpretation of data, some relations were used such as odd/even hydrocarbons C21 and C22, total short and long chain fatty alcohols, the coprostanol + epicoprostanol divided by total sterols and epicoprostanol/coprostanol. The results of the ratios showed a terrestrial origin of the organic matter with a clear predominance of the contribution of the mangrove higher plants of the region. However, there is a discrete introduction of petroleum hydrocarbons and untreated domestic sewage in isolated points of the Estuarine-Lagunar System of Cananéia-Iguape.

ASSUNTO(S)

álcoois graxos cananéia-iguape cananéia-iguape esteróides fatty alcohols marcadores orgânicos moleculares molecular organic markers n-alcanos n-alkanes steroids

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