Is Atrazine Turning The Freakin’ Frogs Gay!? – #2

As I said in my previous blog post, the story of the gay frogs, at its core, is the story of how lazy journalists helped charlatans to become victims so that they can circumvent the scientific method and directly scare the public. It’s a story that started with the publication of research that showed a herbicide negatively affected amphibian development, and ended with sexually explicit and harassing emails, withheld research, unrepeatable results, and outlandish conspiracies. It’s the story of American biologist and professor of Integrative Biology at the University of California, Berkeley, Tyrone Hayes. A man who was able to cloak his anti-science views in concern for the environment. 

Picture of Tyrone Hayes

Hayes grew up in Columbia, South Carolina, in an area where reportedly fewer than forty percent of residents finished high school. As a young boy, he was fascinated by the idea of metamorphosis and spent much of his adolescence studying the local wildlife. In sixth grade, he was accepted into a program for the gifted and later would receive a scholarship to study at Harvard in 1985. He would later move to Berkeley where, after completing his doctoral research, he would take an academic position at the university. In 1997, the consulting firm Eco Risk, Inc. paid Hayes to join a panel of experts conducting studies for Novartis (later Syngenta) on the herbicide atrazine.  

Atrazine is a selective herbicide that can be used both before and after the emergence of a crop or tree to control grass and broadleaf weeds. The herbicide is mainly absorbed through the roots of weeds and then transported to the actively growing tips and leaves. It then kills the weed by inhibiting photosynthesis by binding to D1 proteins of the photosystem II complex in chloroplast thylakoid membranes. This blocks electron transport and stops carbon dioxide fixation and the production of energy needed for the plant to grow. Atrazine is currently the most widely used herbicide in Australian agriculture and is the second-most used in the United States after glyphosate, and thus its safety has been thoroughly investigated, and it was discovered that the use of atrazine, consistent with food plant protection practice, will not have any harmful effects on human or animal health or any unacceptable effects on the environment, however this was not what Hayes had found. 

Hayes believed he found a link between the reduction of size of the muscle surrounding the vocal cords of tadpoles and the herbicide and hypothesised that atrazine was reducing their testosterone levels. Hayes continued his work looking into the detrimental effects of atrazine and discovered something very strange. When dissecting the frogs, he noticed that some could not be clearly identified as male or female as they had both testes and ovaries. Others had multiple testes that were deformed. 

Syngenta and members of the Eco Risk panel traveled to Berkeley to discuss Hayes’s new findings, however, they were not convinced by his data. According to Hayes, Syngenta brought along a statistical consultant who listed numerous errors in his report and concluded that the results were not statistically significant. Despite not finding Hayes’ work significant, they did not want him to publish his findings, however, the EPA used their leverage to release Hayes from the confidentiality agreement he signed with the company, allowing him to publish his findings. In 2002, Hayes published his findings in the paper, ‘Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses’, which caused a panic in the agrochemical world, as the paper showed that the herbicide was having an adverse effect on amphibians at concentrations below the accepted US safe contamination level in drinking water.

The object of the research in the paper was to test whether atrazine interfered with the metamorphosis and sex differentiation at environmentally relevant levels. To do this, Hayes exposed three groups of 30 tadpoles (Xenopus laevis) to varying levels of the herbicide ranging from 0.01 to 200 μg/L from 96-hr after the tadpoles hatched until they no longer had their tails. At the end of the exposure period, their length and weight, time to metamorphosis, gonadal abnormalities, and the cross-sectional dimeter of their larynx dilator muscle were recorded. 

What they discovered was that exposure to atrazine at concentration $ 0.1 μg/L resulted in gonadal abnormalities in 16 – 20% of the animals, however, the paper failed to mention the percentage of incidence of abnormalities at each exposure level . This is an immediate red flag to me as, in the past, I have found that any paper that intentionally hides its results usually is not to be trusted. 

The paper reported that Hayes had found decreased muscle diameters in 80% of males exposed to atrazine at concentrations  >1 μg/L. Hayes hypothesised that the herbicide was increasing aromatase (the enzyme that converts testosterone into estrogen) activity and reported that an average adult male Xenopus laevis exposed to atrazine at 25 μg/L had significantly reduced plasma testosterone. The study stated that these results have been repeatedly verified, yet no mention of this data can be found in the open literature, and no data has been submitted to the EPA.

“Dr. Hayes claims not only that his laboratory has repeated the findings many times in experiments with thousands of frogs, but that other scientists have also replicated his results. EPA, however, has never seen either the results from any independent investigator published in peer-reviewed scientific journals or the raw data from Dr. Hayes’ additional experiments,” EPA deputy director Anne Lindsay testified in 2005.

The Eco Risk panel pointed out that the larynx is a very lobular structure which, depending on where you cut through, you would get different thicknesses and criticised Hayes’ poor control. The lack of dose-response relative to the phenomenon of hermaphroditism means that, at best, the paper is useful in identifying a potential hazard to amphibians, but has a long way to go before it can definitively say that this is an issue. 

The EPA, Eco Risk panel, and Syngenta all wanted to repeat Hayes’ findings, however, he resisted doing a duplicate study or answering questions about his data. Still to this day, 16 years later, he refuses to share his data with anyone outside his lab. The EPA could’t even use his 2002 PNAS (Proceedings of the National Academy of Sciences) paper as a baseline to study the effects of atrazine on amphibians, because it contains no data and did not meet the criteria for legitimate scientific work. This raises the question of how such a poor paper could be published in a reputable journal. Turns out that Hayes was able to use a backdoor in the submission process and hand-pick a close friend who worked in the same department to personally edit his study and walk it past peer review. Had it gone through actual peer review, his lack of any real data would have been flagged and it probably wouldn’t have been published. Due to the controversy surrounding the publication of this paper, PNAS would eventually change its policy to prevent people for using this backdoor in the future. 

Nevertheless, the implication of Hayes’ findings were significant, because a decline in frog populations, an “indicator species”, would signal a decline in the health of the ecosystems around the world. The EPA wanted additional studies with a sufficient number of animals, a positive control, orders of magnitude dosing and clean analytical standard. And they wanted Syngenta to pay for it. After all, why should the taxpayers have to pay to find out if a product is safe or not?

Two independent labs in two countries, using the same methodology and 3,200 frogs, set out to see what impact atrazine had on amphibian reproductive health and found…..nothing. No sexual abnormality, no gender bending, no high pitch frogs, no gay frogs, nothing! When confronted with this data, Hayes simply dismissed it as “industry-funded”, obviously forgetting the fact that his own initial research was industry funded. 

Atrazine is one of the most carefully studied and thoroughly tested chemicals in the world. More than 7,000 scientific studies conducted over the past 50 years have clearly established that atrazine, when used correctly, will not have any harmful effects on human or animal health, or any unacceptable effects on the environment. 

Despite being aware of this research, Hayes continues to spread the idea that atrazine is an endocrine disruptor, however, he knows the science is not on his side, and so he must resort to more underhanded methods, but more on that next time. 

About Myles Power (757 Articles)
Hello Internet! My name is Myles Power and I am a chemist from the North East of England, who loves to make videos trying to counter pseudoscience and debunk quackery in all of its various forms! From the hype around GMOs through to Atrazine turning the freakin’ frogs gay, I’ll try to cut through the nonsense that’s out there!

2 Comments on Is Atrazine Turning The Freakin’ Frogs Gay!? – #2

  1. Damn


  2. Sad that propagandist like Hayes are treated like heroes by junk science sources like NPR, TED TV, The New Yorker, etc.


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