Input of organic matter in a large south american tropical estuary (Paranaguá Estuarine System, Brazil) indicated by sedimentary sterols and multivariate statistical approach

Abstract

The Paranaguá Estuarine System is one of the most important environments of the South American coast. Fishing, urban and tourist activities, industries, sewage and the main shipping port for the export of grains in Brazil are sources of environmental impacts. The sources of sedimentary organic matter were evaluated by sterol concentrations which were obtained by gas chromatography with a mass spectrometer (GC-MS). The coprostanol levels were comparatively low, except at sites close to Paranaguá City, where high concentrations have shown sewage contamination. The principal component analysis showed the distinction between sterols from marine (cholesterol, cholestanol, stigmasterol and campesterol), fecal (coprostanol and epicoprostanol) and terrigenous inputs (β-sitosterol). The sterol composition of the sediments indicated that the estuary system is an embayment dominated by inputs of marine organic matter associated with phytoplankton. Terrestrial inputs were detected only at sites close to mangroves, uncontaminated rivers and semi-closed inlets. Fecal input is restricted around Paranaguá City.