Can the mercury contained in some seafood harm a developing fetus?

Dear EarthTalk: Can the mercury contained in some seafood harm a developing fetus?

—Midge Wilson, Utica, NY

Mercury—emitted by smokestacks and released to the environment from common household products like old thermometers—is a persistent heavy metal that ends up in rivers, lakes and oceans and accumulates in the tissues of fish and animals, including people. “Just one seventieth of a teaspoon of atmospheric mercury can contaminate a 20-acre lake for a year,” says Michael Bender, executive director of the Vermont-based Mercury Policy Project.

According to a 2001 Centers for Disease Control and Prevention study, one in 10 American women of childbearing age is at risk for having a baby born with neurological problems due to mercury exposure—this means at least 375,000 babies a year are at risk.

Most states, and the U.S. Environmental Protection Agency, have issued advisories about eating fish that may have high levels of mercury in their tissues. The Food and Drug Administration (FDA) says that women can safely eat 12 ounces per week of cooked fish. A typical serving size of fish is from three to six ounces. However, the FDA advises pregnant and nursing women, and women of childbearing age who may become pregnant, to not eat shark, swordfish, king mackerel or tilefish, which contain high levels of methyl mercury.

In December 2003, the FDA released test results showing that the Albacore “white” canned tuna has three times the mercury levels as the “light” tuna. “FDA’s tests confirm earlier findings that white tuna has far more mercury than light,” says Bender. “Yet inexplicitly, the FDA still refuses to warn women and kids to limit canned tuna consumption—like 12 states have already done—even after their food advisory committee recommended this over a year ago.”

CONTACTS: Mercury Policy Project, 1420 North Street, Montpelier, VT 05602, (802) 223-9000, www.mercurypolicy.org; U.S. Environmental Protection Agency, Office of Water Science and Technology (4301T), 1200 Pennsylvania Avenue, NW, Washington, DC 20460, www.epa.gov/ost/fish/, ost.comments@epa.gov.