Deformed frogs: the saga continuesResearch conducted by University of California-Berkeley scientists claims to show that frogs are affected by levels of atrazine, a widely used agricultural herbicide (also with relatively limited turf uses), at extremely low levels. The researchers, headed by Dr. Tyrone B. Hayes, purport that levels of atrazine as low as 0.1 part per billion, well below levels found in surface and ground waters in many parts of the United States, caused male frogs to develop as hermaphrodites in the laboratory. They concluded that this was due to the conversion of the male hormone testosterone into the female hormone estrogen.
Anti-pesticide activists, ever eager for ammunition to use against the chemical industry, already are singing the study's praises. However, there are critics as well.
Steven Milloy, well-known debunker and publisher of junkscience.com, points out that other studies have been unable to show statistically significant relationships between frog hermaphrodites (in nature) and chemical exposure, including atrazine. Milloy also notes that no one has replicated Hayes' findings. In fact, results of an earlier Hayes study showing that atrazine caused developmental problems in frogs could not be duplicated in a follow-up study.
Milloy thinks this is reminescent of the now-infamous Tulane study showing synergistic endocrine disruption from low levels of pesticides. After other researchers were unable to corroborate the findings, the researcher eventually was forced to withdraw the findings (which, in the end, turned out to be based partly on fraudulent data).