EPA Report Raises New Concerns About Mercury

WASHINGTON — The hazards of mercury entering the environment from coal-burning utility plants is greater than previously believed, and its toxic effects raise new concerns about its place in the human diet, according to a Clinton administration report to be released today.

At issue in the report, being made public four years after a deadline set by Congress, is not the level of mercury in the food chain but the level at which it should be considered hazardous, particularly for pregnant women, children and people who eat large amounts of contaminated fish.

The study has been at the center of controversy as its publication drew near, with some critics saying it is based on outdated or inappropriate data.

Sources who reviewed the document said it avoids setting specific standards for mercury consumption. But a draft report from June 1996, in which few changes were said to have been made, highlights possible hazards for a person who consumes more than 0.1 microgram of mercury each day per kilogram of body weight. That figure is one-fifth the amount currently recommended as a maximum by the World Health Organization.

A microgram is one-millionth of a gram; a kilogram is 2.2 pounds. Although levels of mercury can vary, for an average-weight male this would, for example, translate roughly into eating a 6-ounce can of tuna every five days.

The Environmental Protection Agency, which is issuing the report, had not previously focused on a specific consumption level.

Scientists say mercury poses particular risks for pregnant women and children because it can hinder fetal development and because children’s lower body weight allows less consumption before damage would occur.

By one estimate, the EPA figure would suggest that to protect her fetus, a pregnant woman should not eat fish with a mercury level greater than 0.2 parts per million, and that this should be limited to no more than once a week. The Food and Drug Administration has established a safety level of 1.0 part per million.

“If you eat a full can of tuna every five days, you’re just fine,” said Gina Solomon, a physician and senior scientist on the staff of the Natural Resources Defense Council in San Francisco. But “all those people who fish every weekend and feed their families the fish are at significant risk.”

Mercury has been linked to damage to the brain and nervous system, affecting language, attention and memory. Its hazards have been widely feared for 40 years, ever since quantities of the substance spilled into heavily fished Japanese waters and resulted in one of the world’s most serious incidents of industrial pollution.

The EPA declined to discuss the report’s contents. During revision of the Clean Air Act in 1990, the agency was instructed by Congress to report by the end of 1993 on the effect of mercury in the environment.

Four years after that deadline, the report draws a bead on such sources of mercury as emissions from coal-fired power plants and municipal incinerators, where the burning of such household and industrial waste as florescent lightbulbs, batteries, thermometers and electrical relays release mercury into the atmosphere.

Mercury reaches the dinner plate when rainfall carries it into lakes, rivers and oceans, where it enters the food chain by accumulating in the fatty tissues of such fish as pike, bass, walleye, tuna, swordfish and shark.

The heavy-metallic element’s concentration in such creatures makes it of particular concern to anglers and those whose subsistence diets, particularly native Americans in Alaska, include large quantities of fish.

The report was criticized last week by two Alaska state epidemiologists, who wrote in the journal Science that it should be viewed with caution because its discussion of unsafe levels of mercury in the food supply was based on an acute poisoning episode a quarter of a century ago that sent 6,000 people to hospitals in Iraq after they ate contaminated bread.

“Data from the Iraqi event may not be appropriate for calculating risks from lower-level mercury exposures through fish consumption. The Iraqi exposures were high-dose and acute,” wrote Grace M. Egeland and John P. Middaugh. “In addition, the delay of several years before data was collected could have limited the accuracy of recall of relevant developmental milestones by the mothers of affected children.”