Metal transportation and natural organic matter characterization from rivers of Itacoatiara, Amazônia

Abstract

The natural organic matter (NOM) is critical in cycling elements in water bodies, presenting a more labile fraction and a more recalcitrant, and last is composed of humic substances. Several studies on the characterization of organic matter and quantification of macro and microelements have been conducted in the Amazon, but is largely absent in this approach Itacoatiara region. The main objective of this study is to determine the stock of metals and calculate how much is exported to the Amazon River, in addition to studying the organic matter of black water rivers through a characterization of humic substances, followed by quantification of labile organic matter and recalcitrant . To this end, sediment sampling will be carried (surface) and soil and two water samples at eight locations, five in water bodies of Itacoatiara region, two along the Amazon River and one on the Madeira River (representative of black waters and white). Will be held extraction and fractionation of aquatic humic substances (AHS) of Caru river (blackwater), followed by characterization by UV-Vis, IR spectroscopy, molecular fluorescence, 13 C nuclear magnetic resonance, Offline Tetramethylammonium Hydroxide (TMAH) - GC-MS thermochemolysis. The characterization will include study lability and recalcitrance of aquatic MON method using the kinetics consumption of hydrogen peroxide. In all the samples of sediment, soil and surface water will be quantified concentration of total dissolved metal (Cd, Cr, Ni, Zn, Fe, Mn, Pb, Cu and Ba) using Atomic Absorption Spectrophotometer with atomization Electrothermal (GFAAS) or with atomization by flame (FAAS). The analytical reliability of the results will be verified with the use of certified reference materials and continued participation of the Environmental Sciences Studies Laboratory Proficiency study for metals. With the results it can determine the inventory and how much is exported metal some tributaries to the Amazon River. As for the results of organic matter is expected this work to obtain a broad characterization of MON present in the region inferring their role in carbon cycling. (AU)