Pesticides are mainly used to protect crops and agriculture from the damages of bugs and creatures that like to munch on our food supplies, but they also often have unintended side effects that we don’t know about until they start occurring in nature.
Like atrazine, the popular pesticide commonly used on corn crops to protect from the invasion of weeds. Studies surrounding the pesticide have found the pesticide to cause “sexual abnormalities” in frog populations, like hermaphroditism (possessing female and male sex organs), but it was only just recently that a study discovered male frogs completely transitioning into female frogs who are capable of reproducing offspring.
At first, it might seem like this is simply a neat little trick, but the implications are actually quite damning. The populations of amphibians have been declining around the world for years, and pesticides that potentially remove one sex from a particular species could decimate their numbers even more, says Tyrone Hayes, author of the study.
Perhaps even scarier is that atrazine alters the creation of estrogen, the sex hormone found in both frogs and humans, meaning it could potentially have very real consequences for any person exposed to it.
“If you have problems in amphibians, you can anticipate problems in other animals," Hayes says.
The study itself used two groups of 40 frogs in their experiment to determine the effects of atrazine.
One group of frogs was raised from larvae through sexual maturity in water containing levels of atrazine typically found in environments where the pesticide can be found, emulating an environment one would find near corn crops and the like. The other group of 40 frogs was raised in water containing no atrazine at all.
Researchers discovered that, by the end of their experiment, all of the male frogs in the water without atrazine remained male, but 10 percent of those raised in atrazine water had gained female sex organs (including ovaries), even when their genetics indicated they should be male. And, they could successfully mate with other male frogs to create healthy eggs.
Male frogs exposed to atrazine who did not transition to female were seen to have lower levels of testosterone, decreased fertility and less desire to mate.
Hayes says that these findings have led them to conclude that pesticides are likely just another major factor in the rapid decline of amphibian populations, others being climate change, habitat loss and invasive species.
And while humans are exposed to atrazine less than creatures living in water-filled environments, the estrogen-altering pesticide could be a possible red flag for humans because of how it affects other species, such as causing breast cancer in rats. In fact, the pesticide has been banned in Europe.
"Anytime you see dramatic declines like we're seeing in amphibians and fish…we should recognize that we drink and swim and bathe in that same water," Hayes said.
You can read more about this study in the Proceedings of the National Academy of Sciences journal.
Do you think we should allow atrazine to be used in the United States?
h/t Live Science