Determinação de metais em ostras na Baía da Babitonga, São Francisco do Sul – Santa Catarina (SC)

Abstract

Metals are introduced into the environment through several sources, such as the use of fertilizers and pesticides, combustion processes, industrial wastewaters, and others. Considering that metals are not biodegradable, allowing its accumulation in the environment, knowledge of their concentration levels in living organisms is critical to the health of the animals themselves and humans who consume them. The oysters, like the other animals, have the ability to bioconcentrate chemical components in its structure, may become the major route of transfer of various contaminants by feeding. Therefore, the aim of this study was to determine metal levels in oysters collected in the Babintonga’s Bay, São Francisco do Sul, Santa Catarina. The collections were made in natura in January, February and March of 2014, when there was a higher occurrence of these bivalves. Moisture and ash content were analyzed, which ranged from 74,63% to 82,45% compared to moisture and 3,68% to 5,67% over the ashes. For the determination of metals (Fe, Cu, Pb, Cr, Zn and Cd) oysters were lyophilized and then subjected to an acid digestion in digester block. These metals were quantified through the technique of atomic emission spectrometry by inductively coupled plasma (ICP-OES) using external calibration. The iron levels varied from 149,33 to 536,67 mg/kg, copper varied between 22,67 and 94,00 mg/kg, lead was between 0,67 and 16,67 mg/kg, zinc concentrations ranged from 1070,00 to 3373,33 mg/kg, cadmium varied between 1,33 and 4,00 mg/kg, and finally the chromium was not quantified. Comparing the results obtained with the laws imposed by ANVISA and WHO, some metals such as zinc and lead, have levels over the limits established by these agencies, enphansizing the need for further studies about the presence of these metals in this area.