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C. Rising Concern about a Pesticide's Effect on Frogs

Narrator: This is Science Today. A common pesticide that's already been found to cause deformities in frogs in a laboratory has been found to affect frogs native across the Midwest. These findings suggest that the pesticide, called atrazine, may be affecting other amphibian populations nationwide. Biologist Tyrone Hayes of the University of California, Berkeley, led the study.

Hayes: Probably the biggest thing that we're looking at now is this herbicide atrazine, which we believe induces an enzyme called aromatase, which induces the conversion of testosterone to estrogen and the resulting effect is that males inappropriately express estrogen, which both feminizes and demasculinizes the animals.

Narrator: The current data raise concern about the effects of atrazine on amphibians in general. Yet Hayes says one of the scary things about atrazine is how widespread it is.

Hayes: It's the number one selling herbicide in the world and in the United States, we use somewhere between 60 and 150 million pounds a year. You know, there's virtually no atrazine-free environment.

Narrator: For Science Today, I'm Larissa Branin.