Mercury exposure and elimination rates in captive bottlenose dolphins

Mercury concentration in fish, faeces and exhaled air were investigated in
order to evaluate total mercury exposure through the gut in captive
bottlenose dolphin and escretion via intestine and pulmonary routes.
Results showed that faeces account for elimination of 34-38% of dietary
mercury; while only 0.9-1.2% of alimentary mercury is eliminated through
exhaled air. The remaining complexation of mercury with selenium, forming
insoluble tiemannite granules is discussed as an important mechanism,
compementary to excretion, by which odontocetes are able to cope with
elevated alimentary exposure to mercury.