By Elizabeth M. Whelan, Sc.D., M.P.H.
Posted: Thursday, January 15, 2004

EDITORIAL
Publication Date: January 15, 2004

Last week, the media across North America reported some startling and disturbing news: A study in the journal Science reported that farm-raised salmon -- eaten regularly by millions of Americans and Canadians -- contains elevated levels of PCBs, chemicals now banned but once used by manufacturers for industrial insulation, and legally released into rivers and streams.

PCBs were identified in all stories as "toxins" or "probable human carcinogens" or "a cause of cancer and nervous system damage."

The bottom line in most of the media coverage: Farmed fish consumption may be posing a health threat to millions of Americans and Canadians.

This is not the first time frightening stories about farmed salmon causing cancer grabbed headlines: In the summer of 2003, the Environmental Working Group (EWG) -- an organization that in most stories either was not identified, or was dubbed "a nonprofit environmental research and advocacy organization financed by private foundations" -- made a similar claim..

The take-home message last summer was: A credible, unbiased group of scientists has determined that if you eat farm-raised salmon, you are putting your health in jeopardy. Eat salmon and pay the price -- An elevated risk of cancer.

Similarly, the take-home message in the recent reporting based on the Science article was: Mainstream scientists who published data in a respected journal are sounding a warning alarm about the safety of farmed salmon.

These take-home messages are false on all counts.

First, there is absolutely no credible evidence that environmental exposure to PCBs poses a risk of human cancer (or any other illness). Even workers who are occupationally exposed to high levels of these chemicals over many years manifest no increased cancer rates. At high doses, PCBs can cause cancer in laboratory animals -- but so do myriad naturally occurring chemicals in food. There is no scientific basis for the assumption that low-level exposure to chemicals, natural or otherwise, which at high dose cause cancer in lab animals, poses a human cancer risk, although "regulatory science" is often based on this faulty premise.

My organization, the American Council on Science and Health, phoned the National Cancer Institute -- the folks who are really the experts on human cancer causation -- and asked, "Do you know of any evidence human exposure to trace levels of PCBs in fish contribute to the toll of human cancer?"

Their response was a resounding "no." Couldn't members of the media have made a similar inquiry before they scared salmon lovers?

Second, none of the coverage of the recent Science study noted that among the authors was a scientist whose entire career has been dedicated to attempting to implicate PCBs as a cause of cancer -- hardly an unbiased source. Similarly, when reporting the salmon scare this summer, no member of the media gave even a hint as to what, exactly, is the organization behind it -- the Environmental Working Group -- and by whom are its efforts supported. Readers instead are left with the impression EWG is a group of science-driven academics, perhaps funded by the Tooth Fairy Foundation.

A visit to EWG's Web page should have caused considerable concern among journalists: Conspicuously absent from the site is any reference to scientific credentials or any other information about those who did the study. This omission is consistent with the fact that the EWG president once conceded to the Weekly Standard that the Environmental Working Group does not have a single doctor or scientist on staff.

Third, the mere fact that this article was published in Science does not give the results instant credibility. Scientific conclusions are derived from the studies of dozens, if not hundreds, of articles -- not one. And any review of the literature on the subject of trace levels of PCBs and human cancer will show no causal link.

Fourth, the claim that led to the media frenzy promoting this "salmon scare" was that PCBs (and related industrial chemicals) were "carcinogens" -- and thus by definition posed a cancer risk. In reality, as in the case with most all of the food-cancer scares over the past 50 years, the term "carcinogen" relates exclusively to high-dose laboratory animal experiments -- not to evidence of human carcinogenicity. Indeed scientists long ago rejected the premise that a mouse is a little man -- it is not possible to accurately extrapolate from high-dose rodent studies to human cancer risk.

Unscientific articles that hyperbolize about health risks terrify the public unnecessarily. It is deceptive and unprofessional for the media to uncritically report one published article or the unpublished work of an environmental advocacy group without also defining the term "carcinogen" as being exclusively derived from animal experiments and interviewing top epidemiologists, toxicologists and general public health professionals who would be able to put the hyperbole about risk in perspective

Let's call tripe when tripe is served. Better to serve up fresh, farmed salmon.

Source Notes:  
National Post's Financial Post & FP Investing (Canada)