Dental amalgam largest source of mercury in sewers

and sewer sludge and major source in water bodies and fish;

also a major source in atmosphere, since most mercury in sewer sludge is outgased at sewer plant or after conversion to methyl mercury in the soil.

Of the mercury from amalgam,
about half the mercury in sewers is from dental offices and the other half from excretion into sewers by people with Amalgam fillings(average over 30 micrograms per day)
It only takes the amount of mercury in one average filling to contaminate all the fish in a water body of 10 acres to dangerous levels.

Documented by Gov't agencies
http://flcv.com/damspr2f.html