Mercury in the Environment

The only mercury compounds presenting significant danger to humans are alkyl mercury compounds, of which methylmercury is the most toxic. Studies have shown that both inorganic and elemental forms of mercury can be methylated in lake and river sediments to form these dangerous compounds. The principal sources of mercury in the environment are discussed. For the US and Canada, they are: disposal of mercury used for medical purposes, chloralkali plants, the pulp and paper industry, and agriculture. The levels of mercury contamination in terrestrial and aquatic ecosystems, the levels of contamination in humans which evidence mercury poisoning, and the differences in toxicity between fetus and mother are discussed. The evidence used to develop maximum permissible level standards for mercury is analyzed and discussed.