Mark West

Does eating lots of tuna lead to higher levels of mercury in your body?

Scientifically, there isnít much doubt. The Environmental Quality Institute has amassed the largest database in the United States of hair samples for testing mercury. When mercury gets in your body, those levels are reflected in your hair, and so a number of environmental agencies have asked their members to volunteer to send in samples.

Letís get a few disclaimers out of the way. Those environmental agencies arenít disinterested; they hope that people will be discouraged from environmentally unfriendly practices by reading the outcomes of the research. And Iím not disinterested; I helped with some of the analyses for the research. But the sponsors didnít have any influence on the outcomes of the research. I can say that for sure, because I was there.

And fish consumption is indeed related to body mercury levels ó but the risk is not so great that most people need to push the panic button. The FDA recommends not eating more than two six-ounce cans of tuna a week, which I imagine few would find restrictive. The recommendation is about half that for pregnant women. And for most species of fish, as a report in 2000 from the U.S. National Academy of Sciences showed, the risk of harm from most peopleís current intake of mercury is low.

But the risk does exist, and thereís where the media come in and confuse matters beyond hope. The research suggests that fish consumption explains a good bit of the mercury in peopleís bodies, more than any other factor, and the data are statistically significant. But there are ways to criticize those findings, ways that involve the nature of the sample, or the ways in which the study was conducted ó the ways that the criticism was made in the scientific journals to which the results of the study were submitted. Thatís a normal part of the process of scientific review.

Thatís not how the media work, though. The networks were burned by Ronald Reagan and his bleating sycophants, who repeated the canard that the media were ìliberalî so often and so loudly that the networks themselves came to believe it.

And the networks responded by turning to a peculiar brand of ìfair and balancedî coverage, in which any statement was ìbalancedî by a statement from ìthe other side.î† If a Democrat spoke, a Republican was given the podium. If a scientist talked about global climate change, a spokesman from one of the forty ExxonMobil-sponsored organizations replete with climate-change skeptics would appear. And when EQIís Steven Patch was on television to report the results of this study, CNN, in the interests of ìfair and balanced,î offered time to John Connelly, who was described as a ìseafood industry leader;î heís actually a spokesman from the National Fisheries Institute. And Connelly said:† ìTo try to get people scared about a healthy product like seafood in order to achieve a means to scare them about mercury is irresponsible.î

Thereís ìfair and balancedî at the turn of the century. Not some evidence about why the study came to inaccurate conclusions, or why one ought to have three cans of tuna a week. Just a blanket accusation of irresponsibility from a spokesman from the industry that stands to lose, and then a fade to black.

And thatís how most media coverage of science works these days. Years of scientific research get condensed into a ten-second soundbite ó and then some industry spokesman describes that scientific finding, vetted by other experts in the field, as demonstrating a liberal bias. The two viewpoints are given equal time, so itís all fair and balanced, no?†

Edward Murrow must be weeping.
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Mark West is a professor of mass communications at UNC Asheville.