Why is mercury bad?

Mercury is a persistent, bio-accumulative toxin that has increased at least three fold in the atmosphere and ocean over the past century, posing a risk to human health, wildlife and the ecological balance. The Food and Drug Administration and 41 states warn consumers to limit or not eat certain fish due to mercury levels and ten states advise pregnant women and children to limit consumption of canned tuna, the most consumed fish in the US. A potent neurotoxin, mercury exposures can affect the brain, kidneys and liver, and cause developmental problems. Data from the Centers for Disease Control indicates that 1-in-12 women of childbearing age have unsafe mercury levels, translating into over 300,000 children born each year in the US at risk of exposure to mercury.