A Voltammetric Study on Toxic Metals, their Speciation and Interaction with Nutrients and Organic Ligand in a South Pacific Ocean Region

Abstract

Dissolved cadmium, copper and lead present as labile complexes and non-labile complexes with organic ligand evaluated by anodic stripping voltammetry at natural pH and pH 2, with and without UV radiation, in surface sea water in the Valparaiso Bay. The vertical profiles of these trace metals levels and the phosphate, nitrate and dissolved oxygen were also determined for samples collected in the ocean at 22 miles off the coast. The cadmium profiles resemble those of nitrate more than those of phosphate and dissolved oxygen. Better correlation for plotted metal concentration versus nutrients concentration was established for cadmium nitrates. The complexation capacity of coast natural seat water was studied for Cu ^{+ 2} in samples which have not been subjected to any pretreatment except the 0.45 μm filtration. In order to obtain information about heavy metal biodisponsibility in presence of anthropogenic organic ligand (nitrilotriacetic acid) the stability constant for Pb(II)-NTA complex was determinated in the same sea water samples, at natural pH.