Virtual Posters

Seabirds are the top of marine food chain, accumulating highest levels of pollutants, such as heavy metals. They have been used as biomonitors of environmental contamination The feathers are archives of heavy metal exposures in birds - during the feathers´ growth the organism excrete contaminants accumulated in tissues. The feathers allow non-destructive sampling and permit retrospective study then they are particularly convenient for monitoring contamination in marine environment. Mercury is the heavy metal that suffers smaller exogenous influence in their levels. When feathers are analyzed the results indicate primarily the endogenous deposition. This study compares mercury concentrations in feathers of Skuas (Catharacta maccormicki and C. lonnbergi) from Keller Peninsula (62005’S-58024’W), Potter Cove (62016’S-58037’W) and Cierva Point (64009’S-60057’W) in Antarctic Peninsula with the objective to verify the influence of species and location in the contamination levels. All mercury levels in breast feathers were analyzed in the “Radioisotopes Laboratory Eduardo Penna Franca” at UFRJ. Mean mercury concentrations ranged from 1.85 to 3.95ppm. Concentration in C. maccormicki was significantly higher than in C. lonnbergi (U´=306.00; p=0.0012), but the concentration in different places not differ significantly (KW=0.6547, p=0.7208 for C. maccormicki; U´=16.00, p=0.1905 for C. lonnbergi). Since these birds are migratory, the contamination observed doesn’t represent only local exposures. Although these birds had similar feeding habits during summer, a detailed winter feeding habits is unknown. This might be the key to understand the differences in mercury levels observed. Mercury levels recorded in adult feathers are representative of the total exposure of the individual during the year (migratory and breeding periods). To differentiate between local and global contamination it’s necessary to analyze and to compare mercury levels in chicks and young birds with the levels recorded in adults. The young bird feathers probably will represent local contamination, while adults’ feathers may represent the total exposure that the birds are subjected during the whole year. Future work is necessary in order to investigate the influence of other factors in heavy metal accumulation; with the inclusion of the young birds in this study. Acknowledgements: National Council for Scientific and Technological Development (CNPq/MCT: 557049/2009-1), Brazilian Antarctic Program (PROANTAR), Rio de Janeiro State Foundation of Support for Research (FAPERJ) and Mount Sinai School of Medicine (Fogarty - NIH ITREOH). Instituto Antartico Argentino for their financial and logistical support. Miriam H. Almeida revised the English.