Every once in a while, a story erupts in the media that seems designed to punish all journalists whose life goal it was never to take a statistics course. Such a brouhaha recently broke out in the strange form of a disputatious salmon filet.
A study was a published in Science magazine, depending on your reckoning either the first- or second-leading science magazine in the world, which detailed that farmed salmon had more chemicals in them — notably more PCBS — than wild salmon. There were so many more that the authors of the piece suggested that consumers switch over to wild salmon or not eat farmed salmon any more than once every month or two.
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Proponents of farmed salmon responded immediately that the levels were well within the food chemical standards proved to be as safe.
Not by the standards we are using, the paper's authors said.
The crux of their disagreement was not in the PCB amounts themselves but in two different scales used to measure their numbers' significance. The United States Food and Drug Administration, Health Canada, the European Union have one scale that indicates that you can eat up to 2,000 parts per billion of PCBs in fish without any appreciable risk of cancer.
The United States Environmental Protection Agency says you can consume only 50-parts-per-billion — a 40-fold difference — safely.
You would think that this is a debate that would almost immediately dissolve in the face of what you might call objective evidence. If there were new health studies indicating that the previous FDA standard was 40 times too high, then this should be immediately changed and the EPA scale adopted. If there had not been any changes, then what was an environmental agency doing straying outside its domain and capriciously setting too-strict food safety standards?
Given the conundrum if you thought that the statistics-challenged journalists might close their eyes and point blindly point at one or the other standards, you are generally right.
At best, there was some hand-waving saying that the EPA was using newer numbers and that they — without stated evidence — figured the chemicals acted in concert.
But nothing really cleared up what was clearly an essential contradiction.
Now, I have an answer for you. Blame the aboriginals.
In its explanation of its rationale, the EPA differentiates the U.S. population into two distinct groups.
One is what it calls in politically correct language "the general population." They buy fish products in supermarkets and fish stores that "are harvested over a wide geographic area."
But "the FDA methodology was never intended to be protective of recreational, tribal, ethnic and subsistence fishers who typically consume larger quantities of fish than the general population and often harvest the fish and shellfish they consume from the same local water bodies repeatedly over many years," the EPA writes in explaining its regulations.
Larger quantities is a very relative term. Sport fishermen are cited, but they eat on average only a quarter of a pound of fish a week — one-half or one-third of what the American Heart Association say all people should consume.
Aboriginals are a category unto themselves and alone would seem to justify a new standard.
A 1997 survey indicated that a tribe in Oregon consumed 540 grams (about 1.2 pounds) a day of fresh, dried and smoked fish. They were not unique. A group of four Oregon tribes studied in 1994 indicated that they were eating upwards of 12 ounces (340 grams) of fish a day. Not to mention the non-food use of the species, such as "using teeth and bones for decorations and whistles, animal skins for clothing and rendered fish belly fat for body paint," writes the EPA.
"Attention should be paid to the role of the fishing family with respect to the tribal distribution of fish, the sharing ethic, and providing fish for ceremonial/religious events. Entire communities are exposed if fish are contaminated," they added.
So the EPA based its reconfigured standards not on the widely mixed and generally fishless diet of most North Americans, but the almost the aboriginal reverse of that. Given the vastness of the difference, the FDA has agreed that EPA standards should apply to "local fish consumption advisories."
That is to say, if there are polluted fish in areas where you think aboriginals might be fishing, use the EPA numbers. You would think that chemical amounts alone would matter, regardless of who you are, where you get the fish or what your ethnic traditions are.
But no — the EPA most assiduously does not make any general suggestion about what even the most fish-mad white people living in cities and going to their local market should do, save that the FDA's standards apply to them. Bizarre, if not to say racist and anti-urban.
Equally problematic is the fact that, according to the EPA standards, the Science findings mean the aboriginal groups they are charged with protecting should significantly lower the amount of salmon they are eating — even if they are from wild stock that are not affected by any particular local pollution.
Aboriginals, if they are as health conscious as the authors of the Science study, should cut their consumption from what may be 12 largely salmon meals a month to half that. Traditions be damned.
And if that advisory doesn't apply to them, then that too is racist.
What does this say about statistics confusing the media? Andrew Lang most likely got it right when he described someone who "uses statistics as a drunk man uses lamp-posts — for support rather than illumination."
