Last summer, we wrote a post, Rachel Carson’s Legacy, about troubling chemicals called endrocrine disruptors, potentially harmful to both humans and frogs, that are in herbicides and pesticides, as well as in plastic, cosmetics, and many consumer products. We followed up with a post about Berkeley professor Dr. Tyrone Hayes‘ studies of one endocrine disruptor, Atrazine, a widely-used weed killer, and its effects on frogs. Some of these effects included “intersex” frogs—male frogs that developed with female characteristics.

Recently a new study by Dr. Hayes has brought increased media attention to this issue.  As reported in the article, Weed Killer Creates Mr. Moms (Science News), Atrazine was added to water in the laboratory’s frog tanks in concentrations of 2.5 parts per billion—the same amount that might be found in rivers and streams, downstream of cornfields, golf courses, or domestic lawns, where it is used as a weed killer.

Dr. Hayes and associates found that one-third of the frogs raised in the water with Atrazine behaved like females, even sending out chemicals to attract other males. Out of the  forty frogs he studied, four had high levels of estrogen, and two actually developed female reproductive organs.

The EPA has determined that up to 3 parts per billion of Atrazine are safe in U.S. waterways. But according to Dr. Hayes’s studies, that’s too much. Even minute amounts potentially harm frogs—and humans as well. Endocrine disruptors have been associated with various cancers and reproductive birth defects in boys.

Recently, sixteen cities in six Midwestern states sued the Swiss corporation Syngenta, which manufactures the chemical, for the costs of expensive water filtration systems needed to keep drinking water safe.

Scientists at Syngenta continue to assert that Atrazine is completely safe (despite the fact that it’s been banned in Europe).   When I looked up the topic on google news, I found two Syngenta-sponsored sites with names such as “Atrazine Safe to Wildlife” and “Atrazine and Frogs.” Their website denies the “baseless activist” claims.

As Randall Amster writes in his post, Silent Spring Has Sprung, on Truthout, and reprinted on the Huffington Post, these denials from Syngenta are similar to the backlash Rachel Carson received from chemical companies when she exposed the dangers of DDT in her groundbreaking 1961 book Silent Spring. He writes:

In [Silent Spring], Carson famously argued that the pesticide DDT was responsible for negative impacts on the environment, animals and humans alike, despite disinformation spread by industry and government officials about its purported safety and utility in agribusiness. Silent Spring is often credited with starting the modern environmental movement, yet today we are facing equivalent challenges and similar campaigns to conceal the potential dangers of toxic chemicals in our midst.

Below is a video from the Huffington Post Investigative Fund about atrazine:

See also the New York Times article, “Berkeley Scientist Studies Raise Corporate Hackles.”