Mercury in immature and adults Herring Gulls (Larus argentatus) wintering on the Gulf of Gdańsk area

This study presents total mercury concentrations (HgT) in selected tissues and organs (blood, muscles, liver, kidneys, feathers and claws) of the herring gull (Larus argentatus) in order to assess the environmental pollution in the coastal zone of the southern Baltic. Dead, frozen birds were collected in the vicinity of Wladyslawowo between December 2009 and March 2010, an exceptionally severe winter — a total of 13 specimens; 6 adults (>4 years old) and 7 immature birds (≤4 years old). Mercury concentrations in all analyzed samples exceeded the detection limit. The lowest average concentration, at a level of 0.4 μg Hg g−1 (d.w.) was observed in the muscles of adult and immature gulls while the highest, at a level of 3.3 μg Hg g−1 (d.w), was determined in the contour of immature gulls. A significant linear correlation was found between mercury concentration in the blood and the concentration in the kidneys and liver, with the coefficients of determination at R2 = 0.87 and 0.86, respectively. This indicates that blood of birds, as a mercury carrier, may reflects the concentration of mercury in tissues and internal organs of birds and, in the case of kidneys and liver, may express long-term exposure to mercury in nourishment.