Liver and breast feather mercury in piscivorous birds of the Caspian Sea: monitoring changes.

Mercury in the liver and breast feathers of the Common Cormorant, and in three species of Grebes from the southern coast of the Caspian Sea, were determined. The Common Cormorant had significantly more mercury in its tissues (liver: 8.5 ± 1.5; feather 8 ± 1 mg/kg dry weight) than Grebes (Great Crested Grebe: 3 ± 0.5, 8 ± 1.5; Black-necked Grebe: 3 ± 0.5, 5.5 ± 1; Little Grebe 2.5 ± 0.5, 4 ± 0.5). Unlike Common Cormorants, Grebes had less mercury in the liver than in breast feathers. Mercury in the Common Cormorant was not different between 2002 and 2008 collections. The mercury threshold for adverse effects is currently 5 ppm, which was exceeded by all but Little Grebes in this study. © Springer Science+Business Media, LLC 2011