More clues in deformed frog mystery

Deformed Leopard Frog
photo courtesy David Skelly/Yale University

Year-by-year, scientists are gathering more information about what is causing deformities and "intersex" (mix of male and female parts) conditions in frogs across North America.  As the clues come in, it becomes more and more obvious that the deformities are almost certainly due to agents humans are introducing into the environment.  

The most recent research, by Yale University's David Skelly, is further evidence that the deformities are not caused by a single culprit, but rather by a suite of estrogen-mimicking drugs, industrial chemicals and pesticides.  Skelly's research studied frog populations in the ponds of four different Connecticut ecosystems: forested landscapes, agricultural areas, suburbs and cities. Not surprisingly, the frogs of forested landscapes were perfectly normal. Those in some agricultural area ponds had deformities.  However, the rate of deformities in urban and suburban areas was THREE times the rate of deformities in agricultural areas!  “The fact that these kinds of estrogens out in the environment can have this kind of effect on a vertebrate — many people would say that that alone is a basis for us to be concerned,” Skelly says of the potential impact of his studies. 

Skelly says drugs that are meant to act as estrogen (though not intended for the environment!), such as birth control pills, along with unintentional estrogen mimics such as the plasticizer agent Bisphenol A (BPA), are not removed by standard wastewater treatment, so they pass easily from our homes and factories into nearby rivers, streams and ponds. For a more complete report of his findings, check out the Yale Environmental 360 website:  http://e360.yale.edu/feature/unraveling_the_mystery_of_the_bizarre_deformed_frogs/2368/