At common environmental concentrations, the popular weed killer atrazine strips male frogs of a key hormone and turns some of them into hermaphrodites, according to new research. The finding raises concerns that the chemical may be contributing to global amphibian declines.
In use for about 4 decades and currently employed in 80 countries atrazine is the most common herbicide in the United States. It's found in virtually all the nation's waterways and is especially prevalent around cornfields in the Midwest. It has also been identified in tests of preschoolers' drinking water (SN: 11/3/01, p. 285: Available to subscribers at How polluted is a preschooler's world?). "There seems to be no atrazine-free environment," says Tyrone B. Hayes of the University of California, Berkeley.
Past research has found no evidence that typical environmental concentrations of atrazine cause premature death or abnormal growth in amphibians. The new research, which H