“Using national blood mercury prevalence data from the Centers for Disease Control and Prevention, we found that between 316,588 and 637, 233 children each year have cord blood mercury levels associated with a loss of IQ.”
What is Mercury? Mercury exists in three forms including metallic element, inorganic salts, and organic compounds. Over 70% of the mercury released into the environment comes from industrial activities like coal-fired electric-power plants, waste incineration, and chlorine manufacturing and mining. Mercury is also found in electronics, thermometers, automobile components, and fluorescent light bulbs.
Dentists are the third largest users of mercury in the United States. Mercury is one component of “silver” fillings or dental amalgams. Extraneous mercury from amalgam fillings gets washed down the drain where it enters the sewage system. Sewage treatment plants are not set up to filter out mercury and therefore it easily passes through the plant and enters a downstream water source. In sediments of the rivers, lakes, and the ocean, metallic mercury is transformed into methyl mercury, which accumulates in concentration up the marine food chain. Tuna and swordfish contain high levels of mercury.
How does it affect me? Methyl mercury is a dangerous neurotoxin that is linked to learning disabilities and developmental delays in children. According to a 2004 U.S. EPA analysis, 630,000 children born annually are at risk of impaired motor function, learning capacity, memory, and vision due to high levels of mercury in their bloodstreams. In adults, high enough exposure to mercury can damage the heart, nervous system, or kidneys.
The developing brain is very vulnerable to exposure to methyl mercury, which can cross the placenta and concentrate in the central nervous system. The blood brain barrier is not developed until after the first year of life and Methyl mercury exposure in the womb causes a measurable declines in brain function.
Mercury is usually found in higher concentrations in the blood than in breast milk. The human body can excrete half of its mercury load over a period of two months.
What is being done about it? Throughout the 1990s, the U.S. Environmental Protection Agency made steady progress in reducing mercury emissions from power plants. Forty-five states have issued advisories warning sensitive populations about dangers of eating mercury contaminated fish. In 2004, the U.S. EPA and the Food and Drug Administration issued a warning to pregnant women and young children to avoid shark, swordfish, king mackerel, and tilefish.
In California, all grocery stores are required to post a warning sign directly on the fish cases, with information about the health risks of eating mercury-contaminated fish.
The state of Massachusettes recently proposed H-4670, a Comprehensive Mercury Management bill, which includes banning the sale of mercury containing products such as thermostats and promote use of safer alternatives when they are available and cost effective.
Rhode Island, Connecticut, and Maine have already passed similar legislation to eliminate the sale of mercury-containing products.
Schettler, Ted, M.D., Solomon, Gina, M.D., Valenti, Maria, and Huddle, Annette (2000). Generations at Risk: Reproductive Health and the Environment. London, England: MIT Press.
Trasande, Leonard, Landrigan, Phillip J., and Schechter, Clyde (2005). Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain. Environmental Health Perspectives, 113(5), 590-96.
