A fish story

Typically, a number of misleading arguments are used together to try to make a point.  Here is an example from the beginning of Dixy Lee Ray's Trashing the planet (page 4).  Describing a newspaper report on dioxin found in fish downstream from a paper mill, Ray questioned both the methods and the motivation of the scientists involved (my comments in italics):

This is what the reporter wrote.  "The flounder contained 1.5 parts per trillion of TCDD, the most potent form of dioxin.  Less toxic forms of the chemical were found from 0.2 parts per trillion to 3 parts per trillion.  A part per trillion is equivalent to one drop in 25 million gallons."

Now that's good, but how can anyone think that such a small amount of a chemical could be harmful?  

There have been a number of studies on the possible effects of dioxin on humans (Ehrlich and Ehrlich pages 167-170).  But Ray simply ignored them, and instead appealed to common sense and personal indignation.

The reporter went on to detail how the test was conducted:

"All nine flounder, including their internal organs, which normally contain high levels of pollutants, were blended together for testing."

Note that the 1.5 parts per trillion of dioxin were dispersed among the nine flounder, and the test included the internal organs, which nobody ever eats, and the skin, which nobody ever eats.

Here Ray has added a red herring to the flounder; the test was to check for contamination from the paper mill, not to see if the fish were safe to eat.

If ever there were a misleading way of making a test and laying it out for the public to see, there it is.

More personal indignation.

On the basis of a trivial 1.5 parts per trillion-not per flounder but in the total of nine flounder mashed up together, guts and all-the EPA proposed a national program to examine the aqueous environment around every paper mill in the country!  

This is math abuse, Ray has confused a concentration with a quantity.  If you poured nine bottles of wine with 12% alcohol into a vat, the result would still be wine with 12% alcohol.  Each bottle would not have had one ninth of 12%.  Likewise, the 1.5 parts per trillion of TCDD is the average concentration of the chemical in the flounder, not the total amount.

Well, that's one way to keep a job going and to keep spending public money.

Here Ray is making an Ad Hominem argument.  The implication is that the EPA employees are more interested in money than the public health, and their results are therefore suspect.

On whose expertise did the EPA rely to decide that one ninth of 1.5 parts per trillion was a sufficient risk to public health to undertake an expensive and extensive nationwide program?

Ray ends with a rhetorical question, and a repeat of the math abuse.  

References

Ehrlich, Paul and Anne The Betrayal of Science and Reason: How Anti-Environmental Rhetoric Threatens Our Future , Island Press, 1996

Ray, Dixy Lee with Lou Guzzo, Trashing the Planet: How Science Can Help Us Deal with Acid Rain, Depletion of the Ozone, and Nuclear Waste (Among Other Things), HarperPerennial, 1990.

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Written by Jim Norton

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