Oxidación aeróbica de sedimentos subóxico-anóxicosimplicaciones para la removilización y liberación de metales

Abstract

In the latest years the concentration levels of certain metal and metalloids in the sediments of the Galician Rías have shown a trend to increase. It is likely that a transfer of these elements to the water column happens during the remobilization of sediments caused by natural events or anthropogenic activities. The inner area of the rías is subjected to activities that remobilize the sediment such as high levels of maritime traffic and dredging and cleaning operations In this study selected samples of surficial sediments of the Ria de Pontevedra were subjected to a procedure of aerobic oxidation to determine the concentration of some elements (Fe, Mn, Cu, Cr, Pb and Hg) released from the sediment to the aqueous phase. The experiment was carried out within five days. Measurements of pH and total concentration were taken both in water and in sediment samples. Furthermore, speciation of metals was carried out in the sediment samples. Metal concentrations were lower in the sediments during aerobic oxidation, being released in the aqueous phase. From an environmental point of view, Cu was the only metal released in quantities that may be toxic for the organisms in the area.