Mercury has a chemical affinity for precious metals, which is why gold mines are the world's number two source of mercury pollution

However, mercury is a highly potent neurotoxin, made even more dangerous by its tendency to accumulate in the tissues of animals, including humans. Mercury pollution that finds its way into the water is the ultimate cause behind widespread mercury contamination of seafood. In addition to causing serious developmental problems in infants and children, mercury poisoning can cause sensory impairments, lack of coordination and other neurological symptoms in adults.

Due to the popularity of mercury amalgamation, gold mining is one of the worst source of mercury pollution on the planet (responsible for 11 percent of the total), second only to coal-fired power plants and other combustion sources.
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