(Beyond Pesticides, August 2, 2007) According to the Associated Press (AP), a new study finds frogs in Vermont living near farms are more than twice as likely as those living elsewhere to have deformities like missing legs. Yale University ecologist David Skelly, Ph.D., told the AP he decided to look at Vermont frogs because the state has been a hot spot during the last 10 years for deformed frogs.
“We went to all these wetlands and cataloged where the deformities were found, and what kind of landscapes seemed to pose higher risks, if any,” Dr. Skelly said. “The answer was, frogs growing up in proximity to agriculture were more than two times as likely to have deformities. This doesn’t say it is chemical pesticides, but you can’t credibly consider this problem of the frogs without at least evaluating whether pesticides are involved.”
Richard Levey, a biologist with the Vermont Agency of Natural Resources, said two common farm chemicals, atrazine and metolachlor, had been found in trace amounts in water from wetlands where deformed frogs had been found. But he told the AP that the concentrations were far below those thought to have any effect on aquatic life.
Research by Tyrone Hayes, Ph.D., a professor of Integrative Biology at the University of California, Berkeley, has found pesticides, including atrazine, to cause serious deformities at levels well below EPA drinking water standards.
While Dr. Hayes’ research has not linked pesticides to this specific deformity, he has shown dramatic effects at extremely low levels. Past research by Dr. Hayes has demonstrated that exposure to doses of atrazine as small as 0.1 parts per billion – a level permitted in drinking water by EPA – turns tadpoles into hermaphrodites – creatures with both male and female sexual characteristics. Dr. Hayes’ team found that up to 20 percent of frogs exposed during their early development produced multiple sex organs or had both male and female organs. Many also had small, feminized larynxes.
Dr. Skelly believes his research has discounted one theory, which was that the deformities are being caused by a naturally occurring parasite, a type of flatworm blamed for frog deformities in the Pacific Northwest. He says the flatworm in question has not been found in Vermont wetlands.
The study, “Ribeiroia Infection Is Not Responsible for Vermont Amphibian Deformities,” is available in the June issue of EcoHealth.
Source: Associated Press