SPECTROSCOPIC STUDY OF HUMIC SUBSTANCES EXTRACTED FROM WATER, SOIL AND SEDIMENT SAMPLES OF THE PATOS LAKE, MS, BRAZIL

Humic substances (HSs) were extracted from samples collected in 4 areas of sediment, water and soil from Patos′ lake - MS. The humic substances from the water were extracted according to Thurman and Malcolm methods (1981) and, those from sediment and soil were extracted as proposed by the International Society of Humic Substances (ISHS). The following spectroscopic techniques were performed in this study: ultraviolet and visible (UV-Vis) and fluorescence emission. The effects of ambient factors as concentration and variations of pH in fluorescence emission of humic substances (fulvic and humic acids) were evaluated. It was observed that the UV-Vis technique and the intensity of emitted fluorescence from humic substances extracted from water has shown linear correlation with the variation of fulvic acid (7.3 the 35.5 mg L-1) and of humic acid (4.8 the 23.9 mg L-1) concentrations, considering just dissolved organic carbon. However, for pH variation (acid, neutral and alkaline media) significant variations were not observed in both, UV-Vis and fluorescence emission techniques.