Heavy metal distribution in southern Sea Lions (Otaria flavescens) from Argentina

Heavy metal distribution in southern Sea Lions (Otaria flavescens) from Argentina

M. Gerpe, D. Rodríguez, J. Moreno, R. Bastida, and J. Aizpún

Heavy metal distribution in southern Sea Lions (Otaria flavescens) from ArgentinaThis is part of Sea Lions of the World
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Description

Marine mammals accumulate heavy metals in their tissues and organs, and diet is the major intake of contaminants in these top predators. In the present study, heavy metal analyses were performed in muscle, liver, and kidney of three adults and one juvenile southern sea lion of both sexes (1.2-2.3 m) found dead on beaches of northern Argentina. We studied both essential (copper and zinc) and non-essential (total mercury and cadmium) heavy metals. Atomic absorption spectrophotometry was used for determination, using cold vapor for mercury and air/acetylene flame techniques for the rest. In both methods, previous acid digestion was made with nitric/sulfuric (Hg) and perchloric/nitric (Cd, Zn, Cu) mixtures. The method’s quality was checked with a Certified Reference Material, and the detection limit was 0.05 μg per g. Mercury concentrations were highest in liver, whereas cadmium mainly concentrates in kidney. Juveniles and adults presented the same tissue distribution pattern for essential and non-essential heavy metals. Hepatic mercury concentrations ranged from 47.6 μg per g (adult male) to 23.3 μg per g (juvenile female), with renal cadmium concentrations between 5.7 μg per g and 0.8 μg per g, respectively. Although a limited number of sea lions were analyzed, there is a tendency to accumulate essential and non-essential metals with age in O. flavescens.

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