Mercury and selenium concentrations in livers and eggs of common loons (Gavia immer) from Minnesota

Mercury and selenium act as mutual antagonists in mature birds, but their t oxicity is additive or synergistic in avian embryos and immature birds. Twe nty eggs and livers C,g from 18 mature and 9 immature common loon carcasses found in Minnesota were collected. Livers and eggs were analyzed for mercu ry and selenium by atomic emission and atomic absorption spectroscopy. Live r mercury concentrations were significantly higher in mature loons compared to those of immature loons and eggs. Liver selenium concentrations were si gnificantly higher in mature loons than those of immature loons, and seleni um concentrations in immature loon livers were significantly higher than le vels in eggs. There was a significant positive correlation between mercury and selenium in loon livers. There was a negative correlation between mercu ry and selenium in eggs.