[Bagor]

" While mercury is known to be toxic in high amounts, scientists continue to debate the health effects of exposure to very low levels. Everyone on Earth has some mercury in the blood stream - the chemical is present naturally, from the belching of volcanoes, and is also present in power-plant emissions. Everyone who smokes cigarettes contributes a bit of mercury to the air we breathe. Mercury is found especially in seafood like swordfish and tuna; a tuna sandwich contains much more mercury than a typical vaccine dose.

http://www.urmc.rochester.edu/pr/News/story.cfm?id=160