• Bird;
  • Common mergansers;
  • Selenium;
  • Mercury;
  • Methylmercury


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. Environ Toxicol Chem 2014;33:421–430. © 2013 SETAC