Coal takes heavy human toll.

• Position: Public Health

STARTLING NEW RESEARCH shows that one out of every six women of childbearing age in the U.S. may have blood mercury concentrations high enough to damage a developing fetus, states the Earth Policy Institute, Washington, D.C. This means that 630,000 of the 4,000,000 American babies born each year could face neurological complications because of exposure to dangerous mercury levels in the womb.

Fetuses, infants, and young children are most at risk for mercury damage to their nervous systems. Studies indicate that mercury exposure also may damage cardiovascular, immune, and reproductive systems. Chronic low-level exposure prenatally or in the early years of life can delay development and hamper performance in tests of attention, fine motor skills, language, visual spatial skills, and verbal memory. At high concentrations, mercury can cause mental retardation, cerebral palsy, deafness, blindness, and even death.

Humans are exposed to mercury primarily by ingesting contaminated seafood. Forty five of the 50 states have issued consumption advisories limiting the eating of fish caught locally because of their high mercury content. Analyses of fish collected by the Environmental Protection Agency (EPA) from 500 lakes and reservoirs across the country found mercury in every single sample. In 55% of them, the levels exceeded the EPA's "safe." limit for a woman of average weight eating fish twice a week, and 76% exceeded limits for children under the age of three.

The largest source of mercury pollution is coal-fired power plants. Airborne mercury emitted by these facilities is deposited anywhere from within a few hundred kilometers of the smokestacks to across continents, far from its source. Biological processes change much of the deposited mercury into methylmercury, a potent neurotoxin that humans and other organisms readily absorb. Methylmercury easily travels up the aquatic food chain, accumulating at higher concentrations at each level. Larger predator species contain the most mercury, which then is passed on to those who eat them.

Since the Industrial Revolution began, mercury contamination in the environment has jumped threefold. The 600-plus coal-fired power plants in the U.S. produce more than half of the country's electricity, burning 1,000,000,000 tons of coal and releasing 98,000 pounds of mercury into the air each year. Power plants yield an additional 81,000 pounds of mercury pollution in the form of solid waste, including fly ash and...