My dad tells a story of his science teacher handing out vials of mercury and allowing students to play with it and watch how it pools. Those days are gone! (I should know, I’m a science teacher.) Today, we aren’t even allowed to have mercury thermometers in school, and there are news reports of schools being evacuated due to a broken thermometer. We now know that mercury is toxic to kids.
Mercury as an atmospheric pollutant comes mostly from power plants, with 72% of it coming from coal-fired power plants. Once released into the atmosphere, mercury contaminates entire ecosystems: fresh and salt water, soil, the substrate at the bottoms of streams, rivers, lakes and oceans, as well as plants an animals. Microorganisms in the water convert mercury to the highly toxic methylmercury. Methylmercury accumulates in the tissues of animals, especially salt water fish like sharks, swordfish and tuna.
Here’s what I think all parents should know about mercury pollution:
- 1 in 10 American women of childbearing age have potentially dangerous levels of mercury in their bodies.
- 410,000 US children are exposed to dangerous levels of mercury in the womb each year.
- 95% of the methylmercury we consume is absorbed through our small intestines and enters our bloodstream, which carries it to the rest of our body. It will eventually be excreted over a period of weeks to months.
- Methylmercury easily crosses the placenta and travels into a fetus’s blood and organs, including his or her brain.
- Methylmercury levels in an unborn child’s blood can accumulate to be higher than the levels in his or her mother’s blood.
- Mercury in both the form of methylmercury (from seafood) and inorganic mercury (from amalgam fillings) has been found in breast milk in studies around the world. However, the level of mercury in a mother’s blood are about 3 times higher than the level of mercury in her milk, so babies are exposed to much more mercury in utero than through breastfeeding. Experts say that the benefits of breastfeeding outweigh the risks of mercury exposure.
- Infants can be exposed to mercury through formula if it is prepared with water contaminated with methylmercury, so experts recommend breastfeeding over formula-feeding in areas with contaminated water.
- Methylmercury exposure leads to impaired neurological development in fetuses, infants and children. It can also delay developmental milestones and cause severe mental disabilities.
The Clean Air Act does not currently have limits on the amount of mercury that can be emitted by power plants, but the EPA would like to set a new Mercury and Air Toxics rule to reduce the amount of mercury and other emissions by 91%. (Learn more about the proposed rule here). Won’t you join me in supporting the EPA’s right to limit mercury emissions? Send a comment to the EPA!
This post will be cross-posted at Moms Clean Air Force.