Sex-related levels of selenium, heavy metals, and organochlorine compounds in American white pelicans (Pelecanus erythrorhyncos).

Liver tissue from male and female adult American white pelicans (Pelecanus erythrorhyncos) were individually analyzed for organochlorine compounds and trace elements. Levels of most organochlorines, specifically SigmaDDT, SigmaPCB, Sigmachlordane, Sigmamirex, dieldrin, and SigmaCBz, were significantly higher in male pelicans compared to females. Only concentrations of SigmaHCH were not significantly different between sexes. Male livers also contained higher concentrations of mercury, cadmium, and arsenic compared to females. Selenium concentrations were not different between sexes, and lead was not detected in any of the samples. Differences in residue levels between sexes were probably due to the female's ability to excrete organochlorines and some trace elements into the egg prior to laying. In addition, differences in contaminant concentrations in prey available to these birds on their breeding grounds and their wintering areas may be influencing sex-related differences.