Comparison between concentrations of mercury and other contaminants in eggs and tissues of Cory's shearwater Calonectris diomedea collected on Atlantic and Mediterranean islands

Trace elements (Hg, Se, Cd, Pb and Zn) and chlorinated hydrocarbons (hexachlorobenzene, pp′DDE and PCBs) were measured in eggs and tissues of a pelagic seabird (Calonectris diomedea) collected in one station of the eastern Atlantic and in three stations of the Mediterranean Sea. Mercury and chlorinated hydrocarbons were much higher in tissues and eggs of the Mediterranean specimens than in those from the Atlantic. Atlantic eggs had thicker shells than Mediterranean ones. In all the specimens selenium levels in the liver were strongly correlated with mercury; cadmium levels were high in the kidney and, to a lesser extent, in the liver. PCB isomers and congeners were studied in detail.