|
(T/EH022) Heavy metals and feeding habits: the effect of weaning in South American fur seals. Gerpe, Marcela1,2, Rodriguez, Diego1,2, Moreno, Victor1, Bastida, Ricardo1,2, de Moreno, Julia1, 1 2 ABSTRACT- The main intake of heavy metals in the higher levels of marine trophic webs is via food, being that the case of marine mammals. The transition period between lactation and predation in this group provides the interesting opportunity to evaluate the influence of solid food in the heavy metal concentrations. The aim of the present paper was to compare the mercury, cadmium, zinc and copper levels in suckling and recently weaned pups of the South American fur seal (Arctocephalus australis). Heavy metal concentrations (wet weight) in liver, muscle and kidney were determined by Atomic Absorption Spectrophotometry (AAS), by the cold vapour technique (Hg) or with air/acetylene flame (Cd, Zn and Cu). The fur seals analysed included 12 suckling pups and 13 recently weaned pups of both sexes. Recently weaned pups showed significantly higher concentrations for all the metals analysed, whereas no sexual differences were detected within each group. Considering the non-essential metals, only Hg was detectable in liver and kidney of lactating pups (max. 0.6 and 0.4 ppm respectively). In contrast, all weaned pups showed detectable concentrations for both Cd (muscle < 0.7ppm; liver < 21.9 ppm; kidney < 29.1 ppm) and Hg (muscle < 0.5 ppm; liver < 7.2 ppm; kidney < 1.0 ppm). These significantly higher heavy metal levels and a clear distribution pattern between organs, strongly suggest that there is a rapid intake of heavy metals during the first months after weaning; the presence of Hg and Cd indicates an early predation on fish and squid. Key words: heavy metals, South American fur seals, feeding habits, weaning |
