Are farmed salmon really safe to eat? Industry, activists and FDA square off.

Don't eat more than half a pound of farmed-raised salmon more than once a month, the Environmental Working Group has warned. The organization, based in Washington, DC, says farmed salmon have unacceptably high levels of polychlorinated biphenyls (PCBs).

But according to a study by Dr. Jules Blais of the University of Ottawa, wild salmon are so full of PCBs that they contaminate lakes in Alaska where they spawn and die. A million of them, his study concluded, release as much of the chemicals as a hazardous waste incinerator. "The more salmon there are, the more PCBs there are," Blais said of his study, which is appearing in the British science journal Nature.

The Environmental Working Group's report comes at a time when salmon consumption in the United States has been on the rise, with flesh farm-raised fillets now in year-round supply and far outselling wild salmon. But the report has been challenged by both the industry and some federal officials, who say it was based on a narrow study that overstates risks to consumers.

Food and Drug Administration (FDA) officials said that the group's test results do not show levels high enough to justify new restrictions. Indeed, they are far below the agency's current thresholds. "It is important to know that at this point the FDA advice is that consumers should not alter their consumption of salmon," said Terry Troxell, an FDA official. "Fish is an excellent source of protein."

Complicating matters further, the group suggests consumers buy wild salmon rather than farm-raised fish. But separate Washington state studies during the past decade have found higher levels of PCBs in wild chinook caught in Puget Sound than those in most of the farm-raised fish sampled by the environmental group. Farmed samples were purchased at grocery stories in Portland, San Francisco and Washington.

The FDA now is reviewing PCB levels in salmon as part of a broader effort to redefine acceptable risk in a chemical-laden world. Currently, the agency tests to ensure that PCBs do not exceed 2,000 parts per billion in salmon, which is far above the average 27 parts per billion detected in the 10 samples tested by the environmental group.

However, another federal entity --the Environnmntal Protection Agency--assesses the risk differently. It recommends restrictingconsumption of fish with much lower PCB levels than the standards set by the FDA. Those lower guidelines were cited by the Environmental Working Group study's authors.

PCBs are long-lived chemical compounds, once used in industrial insulators. They have been linked to increased risks of cancer and fetal-development problems, and their use was banned by Congress in 1976.

FDA officials say that human consumption of PCBs has dramatically declined, by roughly 90 percent, in the past 30 years. But the chemicals still can be found in everything from catfish to polar bears to the human body.

Farmed salmon--reared in floating net pens--have come under increased scrutiny because their diet includes fish feed that in some instances has been found to have significant levels of PCBs. Salmon farms are located in the coastal waters of Washington state, Maine, British Columbia, Chile and northern Europe.

The BC Salmon Farmers Association called the Environmental Working Group report "seriously flawed," and misleading to consumers. Industry officials say they have worked hard to produce cleaner feed and that the PCB levels documented in the report are safe levels.

"Salmon farmers are concerned about meeting food standards. That's the basis of our operations," said Alex Trent, acting executive director of Salmon of Americas.