Study Counters Fears That Mercury in Fish Poses Risks

CHICAGO —  Scientists reported Tuesday that they found little risk, even to children and pregnant women, from low levels of mercury that ocean fish pick up in the aquatic food chain.

The report came from a study in the Seychelles, the Indian Ocean island republic whose 65,000 residents eat nearly a dozen ocean fish meals a week and whose bodies have mercury levels 10 times those found in most people in the United States.

Researchers looked at 711 children born to women who ate large quantities of mercury-tainted fish during their pregnancies and followed the children to age 5 1/2. They found no evidence of impaired mental development in the toddlers, which is the main threat that mercury has been theorized to pose at levels found in ocean fish.

Philip Davidson, chief author of the study, said mercury generally shows up in “very low dosages” in fish. In the United States, the allowable level for fish sold commercially is 1 part per million. The fish tested in the Seychelles, the study said, had mercury levels of from 0.004 to 0.75 parts per million.

Thomas Clarkson, the study’s principal investigator, said: “Eating lots of ocean fish isn’t much of a hazard compared to missing out on the benefits from not eating fish . . . overstating the almost negligible risk of mercury could adversely affect millions of people who face the risk of heart disease.”

The University of Rochester study was published in this week’s Journal of the American Medical Assn.

The journal also carried an editorial from an expert at the U.S. Environmental Protection Agency who cautioned that the study’s findings are preliminary and that additional evaluations using more sensitive tests of development are needed “before firm conclusions can be drawn.”

The research team said its findings do not apply in the United States to fish caught in lakes and rivers, for which consumers should follow local advisories about mercury and other contamination.

It also said its findings are at odds with a Danish study of children in the Faroe Islands. It said the difference may be that the Danish study involved consumption of whale.