ENVIRONMENTAL CONTAMINATION AND MARINE MAMMALS IN COASTAL WATERS FROMARGENTINA - AN OVERVIEW

Environmental contamination become an increasing global problem. Diffe rent scientific strategies have been developed in order to assess the impact of pollutants on marine ecosystems. The distribution of toxic c ontaminants in tissues of different marine mammal species - both cetac eans and pinnipeds - has been studied in many ecosystems, as well as s everal related ecological processes, like pollutant accumulation or tr ansfer through the food web. A research program directed towards evalu ating the occurrence of pollutants in marine mammals from the coastal waters of Argentina (southwestern Atlantic Ocean) has been developed s ince 1985, and includes the study of heavy metal contents in stranded or incidentally caught animals. The marine mammal species studied duri ng this period were: the seals Otaria flavescens and Arctocephalus aus tralis, and small cetaceans Tursiops gephyreus, Pontoporia blainvillei , Kogia breviceps and Ziphius cavirostris. In most of the cases, high contents of heavy metals (total mercury, cadmium, zinc, and copper) ha ve been recorded. Moreover, liver showed the maximum capability for ac cumulation of heavy metals in all studied species. The biological and ecological characteristics of each species of the above-mentioned mari ne mammals (feeding habits, age, migratory pathways, or sex) contribut ed to the understanding of the metal sources. Considering the results as obtained during the study period it can be assumed that: (1) The gl obal distribution of toxic contaminants also affects the southwestern Atlantic Ocean ecosystems, and (2) Marine mammals could be appropriate bioindicator species in order to assess this kind of environmental pr oblem.