What are PCBs?

PCBs are polychlorinated biphenyls that were used in manufacturing for almost half a century. When PCBs were found to be toxic, the United States banned their use in 1979. There is no scientific evidence showing that PCBs in fish or the environment have ever caused cancer in humans. In fact, workers in industrial settings exposed to PCBs on a daily basis show no higher rates of cancer than the rest of the population.

Are ocean-farmed salmon high in PCBs?

  • Ocean-farmed salmon from Chile, Canada and the USA typically have 1/100 of the FDA tolerance for PCBs. Routine testing shows levels often 1/400 of the tolerance.
  • While the National Academy of Sciences review of PCBs in foods made recommendations on decreasing consumption for other PCB-contaminated foods, it did not mention limiting fish/salmon intake.
  • The FDA recently reviewed the tolerance level and affirmed that it is protective of consumers.
  • The National Cancer Institute states that there is no conclusive evidence that the low PCB levels found in salmon are linked to cancer.

Are ocean-farmed salmon higher in PCBs than wild salmon?

Wild salmon are not routinely tested as ocean-farmed salmon are, but several studies found higher PCB levels in wild salmon than are found in ocean-farmed salmon. These were in the Puget Sound of Washington State and the Copper River of Alaska. Both were government studies of a large sample. PCB levels were not above the FDA tolerance and this fish, as is the case with ocean-farmed salmon, is safe to eat.

Does the number of PCBs in ocean-farmed salmon comprise a significant part of the PCBs people ingest?

Based on the average per capita consumption, people get 8 times the amount of PCBs in a year from eating beef. PCBs from salmon represent about six percent of the total PCB consumption levels.

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What are the most recent PCB tests and when were they done?

Testing of wild salmon was conducted by the Alaska Department of Environmental Conservation (ADEC). These salmon were caught in 2002 and the study was published in 2004. Salmon of the Americas (SOTA) paid for the testing, which was conducted by an independent, non-profit laboratory, Southwest Research Institute (SWRI) and verified by Cantox Environmental. The procedures and testing methodology for the studies are available in the ADEC report (PDF) and from the SWRI labs (PDF).

Is this testing more accurate than previous testing?

The last large scale study to sample ocean-farmed and wild salmon for PCBs, published in 2004 in the Science journal, used the same testing methods the most recent ADEC and SWRI studies. In fact, the SWRI results were verified at the same laboratory that did the large-scale study analysis.

Wild: The study published in Science included species of wild salmon not found on sale as fresh salmon in this sampling. This distorted the average for wild salmon. The ADEC study separates sockeye and Chinook salmon, the principal species sold as fresh, and therefore is more representative of what consumers buy in stores. The ADEC study results are more in line with results from other independent studies of wild salmon.

Ocean-Farmed: The scientists working on the large-scale study tested the ocean-farmed salmon two years before Science published the study, and more than 30 months before SWI tested salmon in the most current ocean-farmed salmon testing. Salmon ocean farming is a dynamic operation, especially with regard to feeding practices. During the time between the collection of the fish and the publication of the Science study, PCB levels in farmed salmon had already dropped significantly.

This was demonstrated by ocean-farmed salmon’s declining PCB levels in FDA market basket studies during the two years preceding the publication of the large-scale study. The SWRI tests recently completed show further declines, as expected.

What do PCB levels in wild and ocean-farmed salmon mean to consumers?

Fresh and frozen wild and ocean-farmed salmon contain essentially the same amount of PCBs. The levels in both are about 1/200 of the FDA tolerance and as stated by the leading public health organizations in the U.S., Canada and Europe, pose no risk to consumers.

The levels currently found in wild or ocean-farmed salmon should not be used to limit consumption to any specific level.

For more information, read the ADEC report »

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