Everything changed for Dr. Tyrone Hayes when in 1998, the largest chemical company in the world asked him to use his expertise to determine if the company’s top-selling product interfered with the hormones of frogs.

The company: Syngenta. The product: weedkiller atrazine.

Hayes, an American biologist and professor of Integrative Biology at University of California, Berkeley, discussed in his nearly 16-minute TEDxBerkeley talk the results of exposing African clawed frogs in his lab to atrazine. He presented an image up on the big screen of frog testes, showing a considerable difference between the controlled and exposed groups.

Hayes said:

“The controlled testes, if you look under the microscope, is full of sperm soldiers ready to go. The atrazine-treated testes, the testicular tubules are filled with cellular debris.”

Hayes explained how after exposure to atrazine, frogs that were genetic males became completely functioning reproductive females. In another frog species, he showed the gonads with “eggs that are bursting through the surface of the male’s testes.”

Hayes took this research to the U.S. Environmental Protection Agency (EPA), but they said, “that’s not really an adverse effect that would stimulate us to reassess the chemical.” He then published the results in prestigious journals, including Nature and National Academy of Sciences.

Still, Hayes didn’t get the response he thought his data deserved. So he expanded his research beyond frogs by connecting the impact agricultural runoff into lakes and other bodies of water could have on people who use those resources for drinking water. 

In collaboration with other colleagues, Hayes was able to show how men living in Columbia, Missouri, who have atrazine in their urine, have a low sperm count and can’t get their wives pregnant. Hayes said, “this is the same amount of atrazine, .1 parts per billion, that we were using to chemically castrate and feminize our frogs.”

It gets worse. Men who apply atrazine on fields in California “have 24,000 times the atrazine in their urine than we use to chemically castrate frogs and fish.”

In his talk, Hayes goes into the correlation between atrazine exposure and cancer: “If you look at prostate cancer, there’s an 8.4-percent fold increase in prostate cancer in their factory where they make atrazine in a community that’s 80 percent black.” Those percentages underscore the fact that those who suffer most from the environmental impacts of harmful chemicals tend to be the socioeconomically-disadvantaged and racial or ethnic minorities.

Hayes concluded his talk by sharing this Albert Einstein quote: “Those who have the privilege to know, have the duty to act.”

After a round of applause he explains, “Now, I’m here. Now, you are here. You are privileged and you have a duty. And I have reason that we can change the past, but only if we act now while it is still the future.”

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