The subject of the present study was the piscivorous common mergansers (Mergus merganser). The total mercury (THg), methylmercury (MeHg), selenium (Se) inorganic mercury (InHg; THg - MeHg), percentage of THg that is MeHg (%MeHg), molar ratios (THg:Se, MeHg:Se, InHg:Se), and their mutual relations in livers and kidneys were determined in ducks from an Se-deficient area in Poland. The authors verified a hypothesis that, as a result of living in an Se-deficient region, mergansers from Poland should have higher THg:Se ratios than other waterbirds with similar THg tissue levels. Although a comparison of healthy mergansers from Poland and Canada showed similar THg tissue contents, the group in the present study had a few times lower Se levels and higher THg:Se ratios (overall means >1.7 in both livers and kidneys in all studied individuals) than the Canadian group and other European and North American waterbirds. The authors found significant correlations between various relations, including MeHg-THg, InHg-THg, Se-THg, %MeHg-THg, InHg/%THg-THg, %MeHg/THg-InHg, %InHg/THg-InHg, MeHg:Se-THg:Se, InHg:Se-THg:Se, InHg:Se-MeHg:Se in liver and InHg-THg, Se-THg, Se-InHg, %MeHg-THg, %MeHg-InHg, %InHg/THg-InHg, THg:Se-THg, InHg:Se-THg, MeHg:Se-MeHg, THg:Se-InHg, InHg:Se-InHg, and InHg:Se-THg:Se in kidney. It is likely that the main factor responsible for the high value of THG:Se ratio (>1) in mergansers from Poland is Se deficiency in central and northern Europe. Therefore, this element is unlikely to participate in the detoxification of Hg in these birds.
Keywords: Bird; Common mergansers; Mercury; Methylmercury; Selenium.
© 2013 SETAC.