An estimated 60,000 babies born each year in the United States face a serious threat of learning disabilities or other neurological damage because their mothers ate fish contaminated with mercury during their pregnancies, a national panel of scientists reported Tuesday.
A committee of the National Academy of Sciences concluded that a controversial mercury guideline set by the U.S. Environmental Protection Agency is "scientifically justifiable." Some members of Congress and industries had criticized the guideline as too strong, but the scientists say it actually offers "little or no margin of safety" for the children of pregnant women who eat large quantities of fish and other seafood.
Mercury is found in fish around the world, but areas with particularly high levels include the San Francisco Bay area, the Great Lakes region, some Northeastern states and the Florida Everglades.
In the Bay Area, the state for years has warned people not to eat fish caught in the bay, especially striped bass. But many people, particularly poor minorities, still fish there to feed their families.
The scientists said that for most adults, the risks are low, and they should continue to eat fish because of the beneficial health effects. But the researchers cautioned women of childbearing age to watch their consumption because small amounts of mercury can alter brain development in fetuses.
"The population at highest risk is the children of women who consumed large amounts of fish and seafood during pregnancy," the scientists said.
The panel of scientists say about 5% of Americans consume a "high level" of fish, defined as about 3.5 ounces a day.
Regulation of mercury--which is emitted mostly by coal-fired power plants--has been controversial for decades.
Five years ago, the EPA set a new guideline for mercury exposure that has been opposed by electric utilities and the fishing industry. As a result, Congress asked the National Academy of Sciences to weigh in on the guideline, and banned the EPA from imposing new mercury-reducing regulations on power plants until the review was complete.
Environmentalists on Tuesday said the report is a strong signal to the EPA to act quickly to regulate the power plants. They say mercury is as dangerous an air pollutant as lead, yet regulations lag behind by 20 years.
"This study blows away the last excuse for delay. Now it is time for EPA to stop the toxic mercury pollution that continues to pour from America's power plants," said David Hawkins, a senior attorney at the environmental group Natural Resources Defense Council.
A representative of a national utility group said Tuesday that the industry will not dispute the panel's findings.
"These are eminent scientists. What they said is absolutely critical," said Paul Bailey, a vice president of the Edison Electric Institute, which represents most major electric utilities. "They have further validated the fact that we need to be concerned about mercury levels in the environment."
But, Bailey said, what is yet to be determined is how much power plants contribute to the risk from eating fish, and how much emissions can be reduced without imposing a big financial burden on utilities and ratepayers.
The utility industry opposes a bill introduced in Congress that would force power plants to reduce mercury emissions 90% by 2005.
The EPA is expected by the end of the year to declare that regulations on the industry are necessary, but will take longer to actually propose them.
Under the guideline reaffirmed by the scientific panel, a "safe" daily dose of methylmercury is 0.1 micrograms per kilogram of a person's body weight. That is five times more stringent than a standard currently enforced by the Food and Drug Administration in regulating fish.
The EPA says a typical U.S. consumer, who eats on average less than a third of an ounce of fish per day, would be exposed to considerably less mercury than its guideline permits.
In California, some Asian Americans eat three to four times more fish than average consumers. Moreover, fish consumption is on the rise, with Americans spending $50 billion a year on fish and shellfish.
"One can of tuna fish a week for a pregnant woman would put her over the threshold," said Michael Bender of the environmental group Mercury Policy Project.
Robert A. Goyer, chairman of the scientific panel and a professor emeritus at the University of Western Ontario, said the EPA's guideline is "generally adequate to protect most people." But, he said, "trends in methylmercury exposure, including regional differences, should be analyzed, and so should sub-populations whose diets are high in fish and seafood."