Resumo

GONZALEZ OREJA, José Antonio. El coprostanol como biomarcador de la contaminación fecal: Una revisión de sus aplicaciones en el medio marino. Rev. Soc. Quím. Méx [online]. 2002, vol.46, n.4, pp.341-348. ISSN 0583-7693.

Coprostanol as a biomarker of fecal pollution. A review of its applications to the marine environment Fecal pollution in waters has been classically evaluated by means of microorganisms counting, such as Escherichia coli. However, these methods exhibit several difficulties regarding their applicability. Therefore, other indicators have been proposed, such as several compounds derived from steroid molecules. Currently, coprostanol (5β-cholestan-3β-ol) is the most widely applied chemical biomarker of fecal pollution. Coprostanol, a metabolite of its biological precursor, cholesterol, is produced by human symbiotic intestinal microorganisms. As coprostanol is easily degraded under aerobic conditions, its detection in well oxygenated environments is considered as an indication of a recent sewage pollution. Under anoxic environments, on the other hand, its degradation happens really slowly, which facilitates the analysis of its concentrations as a biomarker of fecal pollution due to sewage spillage. Methods of coprostanol analysis involve a multi-step process which imply first a lipidic extraction, then the fractionation of the sterol component by means of thin layer or column chromatography, and finally, the identification and quantification of the interest molecules by gas chromatography or mass spectroscopy. More recent methods simplify this protocol in just one cycle which match various previous steps. The main focus of the investigations which consider coprostanol as a biomarker of fecal pollution in marine, coastal and estuarine environments is to report about spatial variations in fresh inputs of organic matter, which fecal origin is to be assessed by analyzing sediments and/or water samples. A lesser number of papers have simultaneously taken into account temporal variations in sewage pollution, revealed by studying vertical sediment cores. Finally, coprostanol study also allows to enhance knowledge of sediment geochemistry.

Palavras-chave : Fecal pollution; chemical biomarkers; coprostanol; 5β-cholestan-3β-ol; sewage spillage; marine environment; coastal waters; estuaries; spatial and temporal variations in fecal pollution; sediment geochemistry.

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