Twice in the past 14 months, University of California junk scientist Tyrone Hayes (search) generated mass media hysteria with his "research" claiming to link the widely used herbicide atrazine (search) to sexually deformed frogs.
Though both studies were immediately debunked in this column, you don't have to take just my word for it anymore.
Now, even the Environmental Protection Agency (search) is weighing in against Hayes' claims. And on the odd occasion the typically anti-science EPA staff and I agree that a study has no merits, you can take that conclusion to the bank.
The EPA's Science Advisory Panel, comprised of experts from outside the agency, will meet next week to consider the data pertaining to allegations that atrazine causes developmental problems in amphibians, most notably deformed sex organs in frogs.
In preparation for the meeting, EPA staff prepared a "White Paper on Potential Developmental Effects of Atrazine on Amphibians," concluding in bureaucrat-ese that the Hayes-induced panic is unfounded: "the available data do not establish a concordance of information to indicate that atrazine will or will not cause adverse developmental effects in amphibians."
Hayes claimed in an April 2002 study that concentrations of atrazine as low as 0.1 parts per billion (ppb) supposedly caused either multiple or both male and female sex organs in male frogs. Atrazine is sometimes detected at 20 to 40 ppb in surface water.
But since atrazine had been widely used for decades without being linked to frog deformities, I pointed out there was no reason to assume that whatever happened in Hayes' laboratory was happening to any notable extent in the real world -- a point reinforced by other scientists' failure to validate Hayes' bizarre claims.
The EPA now concurs in its White Paper that Hayes' study "did not show a clear-dose response that demonstrates a causal relationship between atrazine exposure and amphibian developmental effects."
Although Hayes claims his results have been verified, "additional data have not yet been provided in the open literature or submitted to EPA," says the agency in questioning Hayes' credibility.
Then in November 2002, Hayes published more laboratory results once again claiming low concentrations of atrazine were linked to frog deformities.
But Hayes' results were contradicted by a basic law of toxicology: the higher the dose, the greater the rate or severity of toxic effects. Hayes reported that frogs exposed to 0.1 ppb of atrazine had triple the deformities of frogs exposed to 25 ppb of atrazine.
The EPA states in its White Paper: "[Hayes'] data did not show a clear dose-response relationship."
Hayes' November 2002 lab results were accompanied by results from research in "field" -- that is, data on frogs in the wild.
Hayes supposedly found frog deformities at sites with measurable concentrations of atrazine.
The EPA's White Paper elaborates, "like the laboratory study, this study was unable to establish a quantitative dose-response relationship. Notably, atrazine was often measured where it was not reportedly used. Moreover, it is likely that other chemical contaminants were also present but not measured."
Summarizing Hayes' and other atrazine studies, the EPA states: "none of the laboratory studies fully accounted for environmental and animal husbandry factors capable of influencing endpoints which the studies were attempting to measure... poor water quality (e.g., low dissolved oxygen, high ammonia) could have created environmental conditions unfavorable to optimum survival, growth and development."
Summarizing the field studies, the EPA states: "The Agency also concludes that the currently available field studies are of limited value due to the high variability in environmental conditions under which the field-collected organisms lived, uncertainty as to amphibian development status and condition at the initiation of the studies and an inability to relate the co-occurrence of atrazine with key developmental windows for the organisms under investigation."
"Overall, the weight-of-evidence based on currently available studies does not show that atrazine produces consistent, reproducible effects across the range of exposure concentrations and amphibian species tested," sums up the EPA.
Despite its throttling of Hayes' work, the EPA unfortunately leaves the door open for future freaky frog hijinks -- probably as a sop to Hayes and his mindless atrazine-hating, eco-extremist supporters.
The EPA notes that while the evidence doesn't indicate atrazine has caused harm, it doesn't prove atrazine can't under some unknown conditions possibly cause harm. More research was recommended.
While the EPA White Paper is reassuring about atrazine, don't expect this story to be reported by the media. When it comes to junk science, it seems, good news just isn't news.
Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).