Mercury concentrations in Common Tern Sterna hirundo and Slender-billed Gull Larus genei from the Shadegan Marshes of Iran, in north-western corner of the Persian Gulf.

We examined mercury levels in several tissues of Common Terns and Slender-billed Gulls collected from Shadegan Marshes of south-western Iran. In both species, total mercury content was highest in feathers followed by liver, kidney and muscle tissue. We found a significant correlation between mercury concentrations in kidney and breast feather (r=0.83, p<0.05), breast feather and liver (r=0.81, p<0.05) as well as liver and kidney (r=0.83, p<0.05). The contaminant levels in the feathers (11.53 and 15.32 μg/g in breast feather and tail feather, respectively) of Common Terns from Shadegan Marshes are higher than those reported for other tern species from elsewhere in the world, but feather mercury of Slender-billed Gull (6.61 and 5.35 μg/g in breast feather and tail feather, respectively) was similar to those reported for gull species worldwide. Mean values for mercury in the feather of two seabird species were higher than the levels known to cause adverse effects.