Atrazine, one of the most widely-used weedkillers, can turn male frogs into females, researchers reported on Monday. “Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults,” Tyrone Hayes of the University of California Berkeley and colleagues wrote in the Proceedings of the National Academy of Sciences. The atrazine can turn male frogs into females that are able to mate and successfully reproduce.
Previously the chemical had been shown to disrupt development and create hermaphroditism in frogs, whereby they develop both male and female features. This latest study of 40 male frogs shows the process can go even further, Hayes said. “Atrazine has caused a hormonal imbalance that has made them develop into the wrong sex, in terms of their genetic constitution.”
Although banned in the European Union in 2004, atrazine is still one of the most commonly used herbicides across the globe. Its endocrine disruptor effects, possible carcinogenic effect, and epidemiological connection to low sperm levels in men has led several researchers to call for banning it in the US. Like many herbicides, it is sold under numerous trade names (see next page).
“Approximately 80 million pounds are applied annually in the United States alone, and atrazine is the most common pesticide contaminant of ground and surface water,” the researchers wrote. It can be transported more than 621 miles from the point of application via rainfall and, as a result, contaminates otherwise pristine habitats, even in remote areas where it is not used.
I’m not all that surprised to hear that Syngenta AG, one of several companies that makes atrazine, has long defended its safety. The company says it is one of the best-studied herbicides available and pointed to prior safety reviews from the EPA and World Health Organization, among others.
Next: Trade names for atrazine
Photo: Tyrone B. Hayes, the University of California, Berkeley