The level of cadmium, lead and mercury in the liver of cormorants

The presented study mas carried out on 80 cormorants (Phalacrocorax carbo) from 1993 to 1996. The group of birds consisted of 40 females and 40 males, 2 year-olds. The birds were selectively shot during the postbreeding perio d in the Olsztyn region near Ostroda and Mragowo. The average level of meta ls in the liver of cormorants shot in 1993 was: Cd - 0.094; Pb - 0.228; Hg - 1.327; in 1994: Cd - 0.141; Pb - 0.259; Hg - 1.864; in 1995 Cd - 0.181; P b - 0.174; Hg - 3.173; in 1996: Cd - 0.189; Pb - 0.218; Hg - 2.370 mg/kg we t mass. The livers of the female cormorants contained more metals than the livers o f the males, as did the cormorants from Ostroda region in comparison to the birds from Mragowo. The results of the study show that the livers of cormo rants were contaminated by cadmium, lead and mercury from the environment. The metals can be a crucial factor contributing to a health hazard for the birds.