Reducing Mercury Pollution from Electric Power Plants: The Technology to Reduce Emissions Is at Hand, but the Bush Administration Seems Unwilling to Require Industry to Use It. That's a Mistake. (Perspectives)
Little, Matt, Issues in Science and Technology
The majority of electricity in the United States is produced by power plants that burn coal, with 464 such plants producing 56 percent of all electricity. But these power plants also are the nation's single biggest source of mercury pollution. Each year, the plants spew a total of 48 tons of mercury into the atmosphere--roughly a third of all human-generated mercury emissions. There is sound evidence that mercury emissions from coal-burning power plants can, in fairly short order, be cut dramatically and cost-efficiently. Yet plans to curtail emissions of this hazardous pollutant have become enmeshed in an intense squabble as politicians and regulators debate the specific regulatory framework to be implemented.
The Environmental Protection Agency (EPA), which is required under the Clean Air Act to regulate hazardous air pollutants, is developing regulations that would require reducing mercury emissions by up to 90 percent in 2007. However, the Bush administration now is asking Congress to pass legislation requiring less stringent mercury reductions and spreading the reductions over a much longer time. In order to stave off this push, Sen. James Jeffords (I-Vt.), chair of the Senate Environment and Public Works Committee, has introduced his own legislation to codify the 90 percent reduction levels by 2007, and he has indicated that passage of this bill is his top priority. Given the significant threats that mercury pollution poses to human health and the environment, along with the recent strides made in improving emission control technologies, the wisdom of following Sen. Jeffords's lead is compelling.
When coal is burned in power plants, the trace amount of mercury that it contains passes along with the flue gas into the atmosphere. The mercury eventually falls back to earth in rain, snow, or as dry particles, either locally or sometimes hundreds of miles distant. According to data from mercury monitoring stations nationwide, the highest deposition rates occur in the southern Great Lakes, the Ohio Valley, the North-east, and scattered areas in the Southeast; basically, in areas around and downwind of coal-fired power plants.
Once the mercury is deposited on land or in water, bacteria often act to change the metal into an organic form, called methylmercury, that easily enters the food chain and "bioaccumulates." At the upper reaches of the food chain, some fish and other predators end up with mercury levels more than a million times higher than those in the surrounding environment. For the humans and wildlife that ultimately consume these species, these concentrations can be poisonous.
In the United States, the primary source of mercury exposure among humans is through consumption of contaminated fish. Women who are pregnant or may become pregnant, nursing mothers, and children are the populations of greatest concern. When a pregnant woman ingests mercury, it is easily absorbed by her blood and tissues and readily passes to the developing fetus, where it may cause neurotoxicity (damage to the brain or nervous system). This damage eventually may lead to developmental neurological disorders, such as cerebral palsy, delayed onset of walking and talking, and learning disabilities. Approximately 60,000 children may be born in the United States each year with neurological problems due to mercury exposure in the womb, according to a 2000 report by the National Research Council. Even after birth, young children who ingest mercury, from either breast milk or contaminated foods, remain especially susceptible to the pollutant's neurotoxic effects, because their brains are still in a period of rapid d evelopment.
To help protect the public against such potential dangers, the Food and Drug Administration (FDA), which regulates commercially sold fish and seafood, issued an advisory in 2001 for those groups of people deemed most at risk. …