Pollutants Cause Change in Frogs...Sex Change that Is

Pollutants Cause Change in Frogs...Sex Change That Is.

A recent study was conducted in a laboratory at Uppsala University in Sweden.

Scientists tested two different species of frogs, and exposed them to an amount of estrogen that is typically found in bodies of water in Canada, the United States, and Europe. Apparently, some pesticides and industrial chemicals can have the effect of estrogen on the body.

What had prompted the study was an early study that had been conducted in the United States. A species of frog, the Rana pipiens male, had been exposed to a chemical in the wild that contained estrogen-like compounds. This exposure had lead to the sex of the frog being completely changed. The Ran pipiens male frog was one also used in the experiment in Sweden at the Uppsala University. The other species of frog was the Rana temporaria, a common frog found in Europe.

Cynthia Berg, a researcher in environmental toxicology and co-author of the study, reports that in the two control groups, the females accounted for roughly fifty percent of the group; a normal ratio for the species of frog. However, in a group that was growing in water that had added estrogen, the females outnumbered the males significantly.

Different levels of the hormone were used among different groups. Even those frogs with the least amount of estrogen in their water had quite a few more female frogs than male. And, in the groups most heavily dosed with estrogen, the number of female frogs in one group was 95%, and in another, 100%.

Cynthia Berg voices her alarm at the situation. The scientists had used only one substance, but in the outside environment, the frogs could be subject to several compounds working together.