Mercury in Fish: FDA Faulted


An FDA scientist criticizes the agency's loose regulations, which allow fish with high levels of mercury into the U.S. and let importers escape scrutiny

Eating fish is good for you, as numerous studies confirm. But there are certain fish, such as swordfish and shark, that you might want to eat sparingly. Large fish belonging to these species often contain high levels of mercury, a neurotoxin, and regulatory agencies are doing a poor job of keeping such specimens off of Americans' dinner plates. That criticism has been voiced by some of the government's own scientists, who believe the system for inspecting imports of fish is weak and can be easily circumvented by savvy importers.

The U.S. imports about 15 million pounds of swordfish a year, caught by fishermen from Chile, Australia, Costa Rica, and two dozen other countries. The hundreds of importers get about $52 million per year from their haul. Retailers and chefs get a lot more: Steaks now go for $16.99 per pound at a local Giant supermarket.

But while swordfish is a premium delicacy, it is also a long-lived predator. As it dines on smaller fish, it absorbs tiny amounts of mercury (from natural and manmade sources), and the metal gradually accumulates in the swordfish's flesh. When eaten, the mercury can harm the developing brains of human fetuses and children. The Food & Drug Administration sets a limit of one part per million (1 ppm) in fish.

When the FDA tested swordfish shipments in 1986, the agency found half the samples from 64 different importers were over the limit. It subsequently ruled that imports of swordfish or shark must automatically be detained when they arrive in U.S. ports. Before the shipments are allowed in, importers must prove mercury levels are under the threshold.

To get the fish cleared by the FDA, however, importers simply have to show that five samples of fish are under the limit. The importer gets to pick the lab to do that analysis. It can also choose the actual fish for testing. That enables importers to game the system, argue the FDA's own scientists. "The gambit by people who ship fish here is that they take the shipments with real small fish, and do their analysis," explains one scientist. "The younger and the smaller the fish, the less mercury it contains." Since those fish pass the test, "they get off automatic detention," he says. From then on, their shipments sail through. "Practically speaking, there is no surveillance anymore," says the scientist.

The FDA now has a list of 382 importers whose shipments are exempt from automatic detention. The result of this inadequate inspection, according to critics, is that half or more of the swordfish and shark that reach the market are over the 1 ppm limit. Those fish "should therefore be discarded, but they are not," says epidemiologist Dr. Philippe Grandjean of the Harvard School of Public Health, an expert on mercury's effects, in an e-mail.

Investigators from the House Energy & Commerce Committee have looked into the problem. "A substantial portion of all large fish are coming in over the safety threshold," concludes one congressional investigator. And in California, the Attorney General's office has sued a number of restaurants and grocery stores to get warnings about mercury in fish posted. "No one should be eating fish that are over the 1 ppm limit," says Edward Weil, Supervising Deputy Attorney General.

The Boston-based restaurant chain Legal Sea Foods is one business that has sought to allay concerns by doing its own testing. Its lab has found swordfish with mercury levels up to 7 ppm. "If it comes in above the limit, we send it back," says Legal President Roger S. Berkowitz.

The FDA was unable to comment in time for BusinessWeek's deadline. But the agency clearly sees a problem: It advises women of childbearing age and children to eat no shark, swordfish, king mackerel, or tilefish.

The word may not be getting out, though. A recent study by the New York City Health Dept. shows one-quarter of adult New Yorkers with worrisome blood mercury levels. These measurements rise with affluence: Higher-income New Yorkers eat more seafood, and more expensive types like swordfish, than those with lower incomes.

The fish industry disputes the notion that importers circumvent the inspection system. It's not that easy, fishing companies argue, because the FDA must approve importers' sampling plans. Besides, says John Connelly, president of the National Fisheries Institute, the current threshold includes a wide margin of safety. "Increasing fish consumption is the most important thing people can do for their health," he says.

But others say the limit may be too high. For people to eat fish safely twice a week, average mercury concentrations should be only 0.2 ppm, Harvard's Grandjean figures. His advice? "Eat fish frequently, but select small species that are low in the food chain and caught in unpolluted waters," he says. Low-mercury fish include tilapia, catfish, trout, and flounder. Most are cheaper than swordfish, so that can be good for your wallet as well as your brain cells.

Carey is a senior correspondent for BusinessWeek in Washington.

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