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Mercury Levels in Seafood Questioned

Substance is known to impair infants and children, but its effects on adults are unclear. Public officials hope to find out.

October 20, 2002|Sharon L. Crenson and Martha Mendoza | Associated Press Writers

Mercury is poison. And yet it is on dinner plates everywhere -- in sea bass served in fancy restaurants, in tuna casserole ladled out at home.

Most of the time, there is so little mercury, it goes unnoticed. But that doesn't mean the mercury in swordfish, shark, trout or snapper is harmless. Eat enough -- or eat enough fish from especially polluted waters -- and it can make you sick.

Too much mercury damages the nervous system, especially the brain. Too much in pregnant and breast-feeding women, or those who may become pregnant, can hurt their babies -- adversely affecting children's intelligence, coordination and memory. Children under 7 are vulnerable too because their young brains are still forming.

But how much is too much? And are adults at risk as well?

Rising public concern about those questions, which have been in the background for years, is prompting public health officials to look more seriously at mercury and its effects. After a four-year moratorium, the U.S. Food and Drug Administration is set to decide this month whether to resume measuring mercury in fish. The Environmental Protection Agency will host a conference beginning Sunday in Burlington, Vt., to discuss cases in which people are believed to have been sickened by mercury in fish.

State and federal officials disagree over what constitutes a safe exposure level; their programs for monitoring mercury in fish are an on-again, off-again hodgepodge full of scientific holes. There are no long-term studies on Americans, and some of the studies that have been done are contradictory or involve people whose diets are far different from that of Americans.

There are those who say mercury in seafood is a menace, perhaps the biggest threat to childhood development since scientists discovered lead exposure lowers IQ. They say emissions from oil- and coal-powered plants are spreading this poison to an alarming degree.

There are others who say the threat is overblown -- that fish, loaded with protein and heart-healthy Omega 3 fatty acids, is so good for you, it outweighs any concern.

The fact is, no one knows.

"We're all looking for the truth. I don't think anybody knows what the truth is," said Dr. Spencer Garrett of the National Marine Fisheries Service.

Suzie Piallat has a name for it: "fish fog." Piallat, of Tiburon, Calif., was tired and achy and she couldn't concentrate. Finally, she went to Dr. Jane Hightower, a San Francisco internist.

When Hightower asked Piallat if she ate a lot of fish, she said yes -- eight meals a week. And when Hightower tested her blood, she found mercury levels of 76 parts per billion, 15 times the amount considered safe by the federal Centers for Disease Control and Prevention.

"I'm a health nut; I've always done the healthy thing. I never heard any of the warnings," Piallat said. "I thought eating fish was good for me."

Piallat -- who cut back on her fish consumption and soon felt better -- can't be faulted for missing those warnings. It is only recently that some doctors have reported that adult patients are being harmed by mercury in fish.

"I see people in my practice, sick from eating way too much commercial seafood, on a regular basis," Hightower said.

Her peer-reviewed study of seafood consumption and high mercury levels in her patients, many of whom report symptoms such as aching joints and exhaustion, is slated for publication by the National Institutes of Health this fall.

There is no doubt that these patients feel sick, and no doubt that they have high levels of mercury in their blood. But, as of yet, no study has proven that the mercury caused their illness, although Hightower notes many of her patients' symptoms are consistent with mercury poisoning.

There are skeptics, and there is much confusion about safe levels and whether they vary from person to person.

"It's not an absolute, like over this level everybody dies and below this level nobody gets sick," said Dr. Henry Anderson, medical officer at the Wisconsin Bureau of Public Health, who studied a family contaminated with mercury after eating fish meals three to four times a week.

"It's like being on a highway; how many miles above the limit can you go without getting arrested? There are a lot of factors and some chance," Anderson said.

Dr. Michael Gochfeld, a clinical professor of environmental and community medicine at Rutgers University in New Jersey, said he sees two or three patients a year with elevated mercury levels from eating too much mercury-laden fish.

"Ironically, these are usually health-conscious people who have shifted their diets away from red meat to fish," he said. "Some people eat 10 fish meals a week."

The latest FDA guidelines recommend that pregnant women and small children eat no more than two meals of fish each week.

The recommendation is based on a study conducted in the Faroe Islands, a remote archipelago in the North Atlantic between Norway and Iceland.

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