Shorts - Mercury Pollution

Media stories about mercury pollution and the metal’s infiltration into the seafood chain usually blame coal-burning electric power plants for the problem. Airborne mercury from these plants can travel thousands of miles on global air currents before it precipitates into waterways and oceans where bacteria convert it into methyl mercury, a potent neurotoxin. Tiny organisms called zooplankton – a staple food for small fish -- readily absorb organic mercury. Mercury gradually travels up the food chain as smaller fish, whose bodies store methyl mercury, become dinner for larger fish – and eventually for humans. China’s 2,000-plus coal-burning plants emit 600 tons of mercury each year along with soot, sulphur dioxide, and nitrogen oxides. The Chinese government requires newer power plants to install equipment that will lessen the pollution that enters the atmosphere, but older plants can forego an expensive retrofit by paying a fee to the government. The U.S. government still has not instituted a policy to reduce mercury emissions. Instead of waiting for the federal government to act, Governor Jennifer Granholm of Michigan ordered her state’s coal-burning plants to reduce airborne mercury emissions 90 percent by 2015. U.S. coal-burning power plants released about 120 tons of mercury in 1999.

Coal-burning power plants are just one part of the problem. State legislatures throughout the U.S. are enacting laws that prohibit mercury thermometers and other mercury-containing products. Manufacturers no longer use mercury to make batteries or paint. In addition, state governments are now beginning to address the contribution of mercury amalgam fillings. Mercury fillings account for 55 percent of all the mercury presently in use in the U.S., according to the EPA. Dental offices and mercury from amalgam fillings excreted in human waste are a major source of mercury pollution in the U.S. For decades, dentists have rinsed extracted mercury amalgam materials down the drain, placed them in a biomedical waste container to be incinerated, or simply tossed them into a regular garbage can whose contents end up in a landfill or burned. Wastewater treatment plants are not designed to remove mercury and other hazardous waste from the environment. Most of it ends up in sludge, which is burned, buried in a landfill, or used in fertilizers. Despite longtime opposition by the American Dental Association, some state dental associations and legislatures are now promoting mandatory use of amalgam separators. These devices, which operate for under $100 per month, can remove over 95 percent of dissolved mercury and particulates before it enters municipal waste water. The mercury is then collected and recycled.

Bender MT. Dentist the menace? The uncontrolled release of dental mercury. Montpelier, VT; Mercury Policy Project/Tides Center: June 2002.

Flesher J. Michigan looks to cut mercury levels. The Seattle Times. August 20, 2005: A7.

Mercurypolicy.org. Over 1,000 tons of dental mercury to be emitted in next 10-15 years (Press Release) April 4, 2005.

Pottinger M, Stecklow S, Fialka JJ. A hidden cost of China’s growth: mercury migration. The Wall Street Journal. December 20, 2004.