Analysis of trace metals Cu2+, Pb2+ and Zn 2+ in coastal marine water samples from Florianópolis, Santa Catarina State, Brazil

Abstract

The determination of trace metal concentrations is an important indicator of toxicity toward species present in ocean environments. Stripping techniques are frequently used, due to their sensitivity and selectivity. In this investigation we were able to determine, efficiently, the concentration of lead(II), zinc(II) and copper(II), in coastal waters, using Differential Pulse Anodic Stripping Voltammetry (DPASV) and Differential Pulse Adsorptive Cathodic Stripping Voltammetry (DPACSV) techniques. For the determination of metal ion detection limits, synthetic samples were used, pH 2 for lead and zinc and pH 9 for copper. In order to check the accuracy of the procedure a certified coastal marine sample (CASS-4) was used and a concentration of 10.3 nmol L-1 for Cu(II) was obtained. The enrichment and recovery method was used for the metals analyzed, the following percent recoveries being obtained: 95±10 (Pb2+), 110±11 (Zn2+) and 95±8 (Cu 2+). The total metal concentrations obtained were considered low, when compared with the indices established by CONAMA, particularly for lead and zinc. For the copper ion the higher concentration may be attributed to its use in the anti-fouling paint, and industrial processes. ©2005 Sociedade Brasileira de Química.