Evaluation of anthropogenic contamination using sterol markers in a tropical estuarine system of northeast Brazil

摘要

The Sao Francisco River estuarine system, located in the Northeast coast of Brazil, has great economic, tourist and social importance. Its waters are used for activities such as agriculture, aquaculture, navigation and fishery, which supplies the surrounding communities. In this study, sterols markers were determined in twenty-eight sediment samples from Sao Francisco River estuary by gas chromatography - mass spectrometry (GC-MS). Sterol analysis was useful to distinguish between anthropogenic and biogenic organic matter (OM) sources in the studied area. Six sterols were quantified, suggesting different sources. Concentrations of fecal sterol (coprostanol) were lower than 500 ng g(-1), suggesting no indicative of severe sewage contamination. However, two stations showed concentrations around 100 ng g(-1) and the values for the coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol ratios indicates sewage contamination. The results in this study may be considered as baseline concentrations to be used as future reference for monitoring programs to prevent anthropogenic impacts. (C) 2016 Elsevier Ltd. All rights reserved.