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(T/EH023) Accumulation of heavy metals in the La Plata Dolphin (Pontoporia blainvillei). Gerpe, Marcela 1,2, Moreno, Victor1, Rodriguez, Diego1,2, Bastida, Ricardo1,2, de Moreno, Julia1, 1 2 ABSTRACT- Marine mammals accumulate heavy metals in their tissues showing different concentrations according to trophic levels and environmental conditions. La Plata dolphin (Pontoporia blainvillei) is a small coastal species endemic of marine and estuarine areas of the Southwestern Atlantic Ocean. Its diet includes numerous species of small fish, squid and crustaceans. The aim of the present paper was to study the heavy metal distribution in different age classes and sexes, to evaluate the accumulation processes and body burden for cadmium, total mercury, zinc and copper. Heavy metal concentrations (wet weight) were determined in eighteen dolphins by Atomic Absorption Spectrophotometry (AAS), by the cold vapour technique (mercury) or with air/acetylene flame (cadmium, zinc and copper). Liver showed the highest concentrations for Hg (max. 8.8 ppm), Zn (max. 29.7 ppm) and Cu (max. 19.0 ppm), whereas the highest Cd concentrations (max. 6.7 ppm) were found in kidney. Adults showed the highest concentrations for all heavy metals, with juveniles and calves in decreasing order, suggesting an age-related accumulation. No differences (p>0.05) were found between sexes within each age class. Body burden distribution were different between juveniles and adults. In the former the highest values for Hg (max. 1.3 mg), Cu (max. 3.7 mg) and Zn (max. 35.8 mg) were found in muscle and the Cd (max. 0.5 mg) ones in liver, whereas in adults was strictly the opposite (2.1, 4.8, 10.4 and 2.2 mg, respectively). We can conclude that P.blainvillei accumulate heavy metals and due to its coastal distribution it may be considered as a biomonitor of its environment. Key words: heavy metals, La Plata Dolphin, accumulation, organ distribution |
