SPECTROSCOPIC CHARACTERIZATION OF DISSOLVED ORGANIC MATTER IN THE UPPER PARANÁ RIVER FLOODPLAIN

Abstract

In the present study fluorescence and UV-VIS techniques were employed to determine the main source of dissolved organic matter (DOM) in different environments of the Upper Parana River floodplain. The following relationships were analyzed: absorbance/dissolved organic carbon (A/DOC), fluorescence intensity/dissolved organic carbon (FI/DOC), fluorescence ratio (FR), and peak wavelength with the highest intensity (PW). The obtained FR, PW and A285/DOC values indicate that most DOM comes from the main river. The obtained spectra of water samples from the different analyzed sites were similar to that of fulvic acid (FA) extracted from soil from the surroundings of these same areas, thus indicating the source of DOM is chiefly pedogenic. Regarding environments influenced by the Parana River, most DOM proved to be autochthonous.