An Environmental Protection Agency official responded that the study misconstrued EPA data and created no reason for the government to change its recommendations on eating wild freshwater fish. An official of a commercial fish trade group said the study examined data on recreational fishing, not farm-raised freshwater fish found in supermarkets.
About 2,500 fish collected from 260 bodies of water from 1999 to 2001 showed the presence of mercury, the report said. The toxic metal can cause neurological and developmental problems, particularly in young children.
The report was prepared for Clear the Air, a joint campaign of the Clean Air Task Force, the National Environmental Trust and the U.S. Public Interest Research Group. The study recommended more restrictions on mercury emissions from coal-fired power plants.
Seventy-six percent of the fish samples exceeded EPA's mercury exposure limit for children of average weight under the age of three, the report said. And 55 percent contained mercury that exceeded the limit for women of average weight, it said. The report assumed that people in both groups ate fish twice a week.
The high levels of mercury raise the risks of neurological problems in young children or in fetuses of women who ate the fish, said Emily Figdor, a clean air advocate at U.S. PIRG and the study's author. She could not say how many more such cases could be expected.
Although the EPA agrees that mercury exposure is a serious public health issue, the Clear the Air study misused EPA's exposure limits, said EPA spokeswoman Cynthia Bergman.
The advocacy group, in saying the mercury exceeded safe levels, applied standards the EPA set very low to be on the conservative and safe side of any possible errors, Bergman said. The study also based its estimates on material not from EPA, taking its consumption estimates from the American Heart Association's recommendation that people ought to eat two fish meals a week, she said.
The report does not create a reason for the EPA and the Food and Drug Administration to change the guidance the agencies gave in March on eating wild fish, Bergman said. The agencies said people should check with state or local authorities to learn the safety of the fish. If no such advice is available, people should eat no more than one six-ounce portion a week and should eat no other fish, they said.
Consumers who buy their freshwater fish at markets should not be alarmed about the study, which looked at sources of recreationally caught fish, said Bob Collette, vice president for science and technology at the National Fisheries Institute, a fish industry trade group.
Most freshwater fish that people eat is raised on farms and is not a danger, Collette said.
The report said reducing mercury emissions from power plants is crucial to reducing unsafe levels of mercury in the fish. It criticized the Bush administration as planning to "delay even modest reductions in mercury from power plants until after 2025."
The EPA's Bergman said the administration had taken a big step forward by deciding to regulate the emissions, but she said technology needed for plants to make the cuts had not yet proved itself. U.S. PIRG's Figdor disputed that, and said some states were imposing earlier deadlines on emissions control than the EPA has planned.