Herbicides interrupt frogs’ sex lives

A study published this week in the Proceedings of the National Academy of Sciences and reported by Scientific American magazine suggest that the cost of killing weeds is killing frogs’ reproductive abilities.
Tyrone B. Hayes of the University of California, Berkeley and his colleagues studied the effects of atrazine, a widely used weed killer, on the African clawed frog.
The researchers found that larvae and tadpoles immersed in water that had concentrations of atrazine as low as 0.1 parts per billion grew into frogs with severely abnormal sexual development. Some 16% of the animals subjected to the chemical had more than the normal number of sexual organs or had both male and female organs. None of the control group had abnormalities.
They also found that the males subjected to the chemical had small vocal organs, and they had lower testosterone levels than are found in normal female frogs.
While the researchers hasten to reassure human beings that they will not be affected by the chemical, the 0.1 ppb concentrations that affected the frogs are 30 times lower than the level U.S. regulations allow in drinking water.
Many believe that frogs and amphibians are the environmental equivalents of canaries in a coal mine – they react quickest to changes in the ecology and serve as a warning to humans.
www.scientificamerican.com